You're not a "problem player", but you're not enjoying the game and you need to look out for yourself and your mental and emotional health.
Go see a psychologist or psychiatrist. A general practitioner should be equipped to hear the problems you're experiencing in your life and forward you on to the appropriate professional with the appropriate specialisation.
During a point when my life was rough and work was stressful I avoided games which I found stressful and confrontational and unpleasant when things were going bad — that meant bowing out of most board games with my friends, because they were keen on strategy games and I wasn't handling losing or going poorly well at the time.
If you feel a game is getting you down and bringing out the worst in you, I do suggest leaving. (But you can keep playing tabletop RPGs if you want to. See the next section.) Your partner may be confused and unsure what's going on; they might've invited you to the game hoping you'd enjoy it and it'd help you with whatever you're dealing with right now. I don't know whether you have out-of-game contact with the rest of the individuals involved — if you don't, your partner can pass on whatever message is appropriate. It may be helpful to tell your partner what's going on for you if you haven't done so already. If you're not comfortable with that, you may at least tell them you find it a rough experience and think you'd be happier sitting out for now.
If there's people you like and want to spend time with, find things to do with them that aren't confrontational. My friends missed me playing games with them, but every so often I'd just hang out beside them while they played, talk, read a book, watch their game, talk with them about it, have fun with them from my non-participant POV and make jokes and so on. I enjoyed doing that. Playing, however, was not the thing for me at that point in my life. There were a few games I was OK with, and I joined in on those games with my friends just fine. Pathfinder probably isn't one of those for you. Find nonconfrontational games you like more, or activities like heading to the cafe, hanging out and talking, seeing movies in or out of home, etc.
If you'd like to continue tabletop RPGs, there are games that may suit you better
There are actually fairly nonconfrontational, failure-light RPGs.
Pathfinder's a game where if you lose on any scale, it's just a loss, things suck, and there's not much good or fun obtained from it. That can be rough even for a person for whom everything else is fine; extra-rough for someone going through some hard times. This is common in the D&D family of games (which Pathfinder is in), though it's more or less serious in various editions or stories.
There's lots of other games where losing on any level doesn't really matter or is actually part of the fun. During those same hard times I was avoiding strategy games, I was playing some of these with my tabletop gaming group, and requested the mood stayed away from heavy stuff. I'll recommend some of the more lighthearted ones I know, everything on this list is free to legally download and play:
- Roll for shoes: In my experience, prone to very lighthearted, potentially fairly whacky games. Players pretty quickly wrestle control over this from the GM, and after a while nobody's in control of this weird game. (Unless the GM is deliberately exerting very strong control over what people can and can't do, which ain't in the rules.)
- Great Ork Gods: a slapstick RPG about orks and the gods who hate them. You play as both the gods and the orks in a group with 7 players or less. This game isn't meant to be taken too seriously, and you should expect to see your orks fail horribly and die at least once in a single gaming session. Them doing so is supposed to be part of the fun. (So don't get attached. Rolling up a new one is quick; you just have to pick a name and roll to see how much each of the seven gods hate them.)
- The game PDF and an additional game scenario can presently be downloaded from the site's front page linked in the tag info.
- You may still find the failure unpleasant. I didn't. Find a good light-hearted narrator who'll make it funny to watch. Don't get invested in your ork's success too much, they'll die sooner or later.
- Lasers and Feelings is a one-page Star Trek: The Original Series parody with the serial numbers filed off. Captain
Kirk Darcy has been struck sick. Go have some fun wacky adventures in the meantime.
- Masters of Umdaar is a pay-what-you-want-including-free variant of Fate Accelerated. It's fairly lighthearted cheesy 80's laser fantasy (like Thundercats and He-Man) and you can really go hammy and silly with it. As part of the Fate engine, failure and complications and setbacks are part of the fun, and you're compensated with a metagame currency called Fate Points which can be spent to generate future success. (That's effectively a bribe to be OK with the Bad Stuff happening. It works remarkably well.) The general perspective is to conspire with your fellow players against your own characters to put them through interesting dramatic situations. There's a lot of catharsis to be had from the experience.
You may be able to bring these to your partner and see if there's a way you can play those — it may involve the Pathfinder group or not. Make sure it's clear to your partner and your gaming group you're after something fun, upbeat, light-hearted, amusing, etc — not heavy or dark or stressful or with an overwhelming number of setbacks.
What you may be experiencing
Specifically, for your interest, because it's the cause of what I was going through and it sounds similar — you may be dealing with perfectionist tendencies. I felt frustrated when I failed at things or didn't do them as well as I expected. I developed an attitude that if I couldn't do something well, why bother. I can say for sure it did have a hollowing, soul-crushing effect on me, dragged out over many years. Through conversation with a psychologist who specialised in things such as anxiety and depression, I was able to examine the shape of the perfectionism bringing various parts of my life down, and find non-perfectionist habits I could use to redefine how I approached those portions of my life for the better. You may benefit from a similar conversation.