Advice please!

I have been battling ocd for over a year now and it likes to switch themes. Currently, it’s attacking my relationship with my girlfriend who I’ve been with since I was in high school over 10 years ago. It first began as an intense feeling that I have to leave or break up with her over dumb little things. Then it changed into a lot of guilt for having any thought about another girl. And the worse is feeling this intense guilt for past things I’ve done in the past while in this relationship. We were so young and I was teenager, but I often found myself watching porn, fantasizing about real other people in my life, and getting off to other girls that I may have known. When I was younger I didn’t think it was bad and that it was just a normal teen boy thing, but 10 years later I have so much guilt about it. And yes I’m with the same girl now. We’ve had our ups and downs, but I know I love this girl and I’m ready to propose to her soon. Anyway, these past mistakes I did when I was younger make me feel like a cheater and I can’t stop ruminating about it. I feel like I have to admit every detail and person I’ve ever had a bad thought about. I feel like if I propose to her and don’t tell her everything, that I’m a lair and didn’t give her the full picture. And the other day one of the girls I thought was hot when I was younger, came up in convo and I just went downhill. Now she knows I deal with OCD and she is very supportive, I’ve told her before that I did some bad things, but never all the details. And that’s all my brain keeps telling me to do. I have so much tightness in my chest and just want to be able to breathe again. But everyone says to not admit or it’ll reinforce the cycle, I’m just not sure how everyone else does that. And at the same time, maybe I am a cheater and just simply a bad person. Idk! I never cheated physically or anything like that, but my past mistakes feel like I did. But again I may just be a bad person! Please if anyone has advice or is dealing with similar things, I’d appreciate the help!

I’m a good man and I know that. My OCD revolves around relationships. While dating someone a truly enjoy, I find myself needing to compulse everything on my mind or else I feel like I’m being a liar or keeping secrets. I also am pretty confident I suffer from false memory ocd. I don’t like to put a label on things but I’m 99.9% sure I do. My compulsions a lot of times come from things I’m not even sure are real. The more thought I put into them, the more I start to believe they are real. One of the worst compulsions I had in my relationship was I had a thought “what if I find my ex more attractive” and “what if I thought the sex with them was better”. I ended up compulsing these things to my gf. After lots of time to think and get a ahold of myself I was able to remind myself that these things weren’t true and I was just in a downward spiral. There was a 2-3 month period where every time I was relieved of something then I would instantly think of something else. These compulsions have caused insecurity in my gf and I feel like a terrible person. Never meant to hurt her at all and was just trying to find a sense of relief. While I know it is not true, I can’t fix things with words and I feel terrible. I would love to hear from people with tricks and strategies that can help. I love my gf and want to fix things and understand this is not a relationship fixer app but I would like to know what are some ways you are able to deal with these kind of things.

So i had really bad pure ocd but recently it’s been sooo much better but i’m in a relationship and me and my bf dated before about 2 years ago then we broke up and now we are back together but i’m having an issue where i will try to go back years and find something i did wrong and i really do not want to find anything to feel wrong about or guilty specifically something i may have done wrong to my boyfriend but the thing is i’m a good girlfriend and i’m very loyal so i don’t want to ruin something for me because of my past if that makes sense like i can’t remember doing anything wrong but my brain keeps going are u sure let’s look at all your interactions with people and it’s so annoying i just wanna live my life in the present does anyone have any tips