You need a heart-to-heart with your SO/DM antes the next session

And you tell them what you just told us, a host of strangers on the internet.

Your problems have little to do with the game, and most likely need to be solved OOC with your SO. Before you play again, you need to share with your SO that you are at your wit's end and have gone on-line to ask strangers for help in a situation where your relationship ought to have provided fertile ground for the two of you to have an OOC conversation about what, in the game, is bugging you.

This is really important: resolve OOC things about communication first, in person, before the next gaming session. The game is nowhere near as important as your relationship.

Here are two possible serials to this situation:

1. You have a discussion and make peace with your SO/GM. The game proceeds.

2. You have a discussion with your SO and discover that your SO is using this gaming situation as a way to create distance between you. (I really, really hope that this is not the case).

   If that's the case, the game is the least of your problems. Address your relationship, and work on it: screw the game.

There are other possible situations. Here is one outcome that can keep the peace in the relationship (@Wibbs, thanks for that point):

You may, after your discussion, arrive at the conclusion that you cannot play in games with your SO as the DM. This is a valid resolution; not all players are compatible with all DMs.

I offer you this answer based on experiences with people and games.

I would like to address something that hasn't been addressed yet by other answers. The behavior that is (rightfully) perceived as bullying by you. Giving you the 'hothead' role in Discord is a line that, in my opinion, shouldn't have been crossed.

This needs to be addressed in a serious talk with everyone. I usually tend to address this kind of thing either immediately after a session (bonus: fresh examples) or at a time between sessions that I request with the other players. Granted, I'm the GM in these situations, so this makes the organisation a lot easier as it comes from an authority figure. However, considering that you have played together for a while now as a group it should be in their best interest to join their usual GM in a conversation.

Teasing can be ok and even good at some tables

Odd references to stairs, the person who always rolls badly except in life-and-death-situations, or a characters' hotheadedness... On some tables, this is the norm. On others, this is ok with some jokes and felt to be shitty with others.

For example, characters always dying next to stairs for some reason is a semi-mythological and self-confirming creation that usually everyone enjoys chuckling about. That a character is an idiot or hothead if the player did not intend for them to act or be perceived in such a way (and that's kind of the important part) is a dig at the player - worst case scenario it can give of the vibe of 'you're doing it wrong' or even an attack on the players' personal character as opposed to the person in the roleplaying game universe.

Address this. Tell them their jokes make you feel shitty, that you were surprised how your character came across to them and didn't intend it to be that way. Then, ask where they want to go from here. Ideally they will be dismayed that you're not having fun and will try and work out a way to fix this.

Ways to fix this

There are many ways to non-awkwardly communicate that whatever is going on right now is too much.

Talking about things beforehand is obviously one of them, but in my experience most people - when prompted - just say they don't have any triggers or anything that makes them uncomfortable.

1. Whisper the person that is doing the uncomfortable thing - unobtrusive, but takes a minute and potentially confuses other party members. Also, they might not notice.

2. The X card. Well-known in-person solution: point at the Card on the table whenever something makes you uncomfortable and the person talking will redirect / stop. In online games, an "X" in the chat or f.e. a Roll20 deck where every player gets one X card is however also a workable option.

3. An — in my opinion — somewhat better variation to the above is the traffic light system which can also be simulated via chat or roll20. It allows for more options in how to proceed. Yellow is 'careful, don't go further than right now' where as red is an emphatic 'STOP'. This means the card can be played (or written in chat) as soon as you get a bit of an 'eh' feeling but there is still the handbrake option.

Usually, after the session there will be a chat about what went wrong if the person that used the sign is comfortable with this.

What if they really don’t care?

That's fine, not every gamer is compatible with every game. This may feel off to you, because after all, you have been playing together in different games... just with you as the GM.

There is, of course, a difference in power dynamics. Or maybe the others have a bit of an 'us vs. the gm' in them and have a hard time letting go of that despite your change of roles. Maybe part of this is even you, adjusting to the difference in power/influence as a player.

In any case, things don't work out. Tell your SO: "Honey, thank you very much for being willing to GM so I can actually play. I'm really sorry, but the group dynamic that has been developing there is just not fun for me so if everyone else is having fun - including you, hon! - then please continue and I'll bow out gracefully."

Or something like that. If they tried GMing in order for you to have fun, then they should be on board with you not participating if you, you know, aren't having fun. I know I myself would be horrified to find out my SO isn't having fun in one of my games and certainly wouldn't want them to force themselves to play or something.

Don't let the GM go into a discussion on what you did wrong or something. It's not worth the hassle because they perceive you to be the problem already. Just ask them to accept it please and that you don't blame them or the others.

While you shouldn’t have to play in a game that you don’t enjoy, I think it would be a good idea to step back and try to understand why this is happening.

You’ve been running this group for a long time. Now once someone else is GMing, they are basically running wild, right? And picking on you? Maybe it’s just random, but maybe there’s a reason for it. I am reminded of a GM who posted a question on this site about how his characters wanted an “evil campaign” and were now running around doing whatever they wanted instead of playing “realistic evil,” and he came to understand that it was probably because they really just wanted freedom of action after being controlled tightly by the GM for so long. I’ve seen this a number of times over the years when a very controlling GM has the tables turned on them.

Assim:

1. They are deliberately outclassing and marginalizing your PC
2. They are teasing you and putting you down
3. They are not following the plot but are running around doing things that come to their mind as fun

This tells me that possibly, they feel like you have been an overly controlling GM/deity for some time and they are enjoying both the freedom of being able to have their characters do what they want (even if there are consequences) and hazing you in some kind of retribution. Naturally you are still trying to be the force of order and control even as a PC, given how used you are to being in charge, and are doing your part in creating an adversarial relationship with the other PCs. However, this then continues their motivation to resist your influence, and now that you’re not in charge, you can’t just stop them with your fiat.

I’m not saying they should be bullying you, but this is an opportunity to learn. Both about being a player from the player’s perspective (a mortal who frequently has a lot less control over their circumstances than they’d like) and about the GM from the player’s perspective (you need them to have a game, but they don’t see themselves as an equal and their actions affect you greatly).

You could just quit. But then what? Take GMing back over? Well, maybe they “got it out of their systems” but maybe they are just going to take this as “oh sure, she can dish it out but not take it” and act up even more.

You could steer into it and use it as a learning experience. The first two lessons to learn are:

1. Your character is not you
2. The plot is not you

I suspect you are entirely too invested in both of these things. Give them up, and focus instead on your relationships with the other people at the table and all of you having fun, NOT at the expense of each other.

You can start playing a hothead character. Why not? That’s not “you” but that’s why we call it role-playing. Next time an NPC y’all are questioning gives you lip, punch him in the throat! That’ll surprise the others. Let yourself off the leash and have fun. Have your character drink too much and dance on the bar. Have fun com the other players to be accepted.

Instead of focusing on the plot (which clearly neither the PCs or the DM care about) - focus on how you can help the other PCs achieve their goals. Be their wingman in the bar. Assist the higher skill characters on skill attempts. Some of the problem is that they don’t believe you are “on their side” - and they’re right. You’re still trying to control them, and that is just about as rude and inconsiderate as them calling you a hothead. Ideally your SO would have clued you in to this, but maybe he agrees and thinks openly discussing it’ll “get him in trouble” with you. (Also be sensitive to that if the GM sides with his SO too much it erodes player confidence in his judgement, so he may be taking a light hand to not fall into that trap.)

As you do this you will learn a lot from the player perspective about how you have to work with other players and how the GM sets a lot of the boundaries for you, consciously and unconsciously, that affect your fun. This will make you a better GM when you resume the screen and if you can show yourself a friend and ally of the other PCs and not just “their boss”, they should be more willing to settle down a little when it happens.

Again, I’m not saying they’re right to bully, and you can always just quit, but I strongly suspect that there’s something to be learned from this and if you can just reorient your thinking to have fun as a player in this game being a bit more chaotic and supporting the other PCs you will come out of it much better.

(As a side note this isn’t rally that much of a RPG-specific dynamic, and can be found in workplace relationships and friend-group relationships - developing the skill to understand why you’re not being accepted and what to do about it is super valuable and it’s actually great to be able to work it out in the safer confines of a RPG.)

For a start this sounds like a great use for the Ferramenta mesma página; it looks like some of your players may be playing a different kind of game than you. I know from my own experience that it is not always easy to adjust to or even recognize you are playing a different game from those you run, because switching which side of the screen you sit on throws off your expectations more than the game style and you miss it in the noise. It is likely that no one is "the problem," rather, you all are acting under different assumptions of what is OK. These three questions in particular seem the most useful for this situation, although exploring the whole list is important and probably worth burning ten minutes of a session on. Use session time, you want to all do it together not individually. The idea is to get everyone on the same page.

Do you play to win?

a) Yes, you totally play to win! The win conditions are…

b) Good play isn’t a win/lose kind of thing

Player characters are:

a) expected to work together; conflicts between them are mostly for show

b) expected to work together; but major conflicts might erupt but you’ll patch them up given some time

c) expected to work together; major conflicts might erupt and never see reconciliation

d) pursuing their own agendas – they might work together, they might work against each other

e) expected to work against each other, alliances are temporary at best

Doing the smartest thing for your character’s survival…

a) …is what a good player does.

b) …sometimes isn’t as important as other choices

c) …isn’t even a concern or focus for this game

You may actually be playing two different games (what you think you are playing and what they think you are playing). For some players Character conflict is completely fine and they won't get why it bothers you, or maybe they don't care if the group succeeds as long as they play their character faithfully and they may not know these things bother you. You can see how this will lead to player conflict. But it is entirely possible this may not be a game for you and there is nothing wrong with that, but you may also enjoy this new game once you are all on the same page. The idea is to get the whole group to agree on a single set of "rules" and see if that solves the problem.

Next before you consider excusing yourself consider or retiring the character, after you all get on the same page you may just want to play a different character in this setting. If you feel your character is not doing anything it is easy to get bored or defensive. It doesn't matter if the other players think your character is fine; if you don't like the character and their interactions, then try building a different character. It is important that todos has fun and that includes you. I have built characters that just don't work with the current group dynamic, so I retired that character and built a another one. It is often easier to retire a character than drastically change the character's personality.

You may even enjoy playing on the other side of the table so to speak, I have enjoyed playing the antagonist in games that I did not enjoy playing one of the protagonists in. This can also reduce your direct interactions with a player if their personality is rubbing you the wrong way. It can even be fun to have your character get fed up and turn on the party (you becoming an antagonist) as long as you discuss it first with the DM.

Lastly don't be afraid to talk to your DM and say you are not enjoying yourself, it is better to get it out in the open than stew and build resentment - especially if you find you are not playing the same game and don't enjoy what they are playing. Not every game or campaign is for everyone; that does not mean you will not like the next one.