Really struggle to understand why this happened to me in the middle of such a good relationship.

Because OCD absolutely lives for bad timing. Bad circumstances exist especially when something is particularly good , which drives them. Your job is to not change your life to accommodate the thoughts ?? they are thoughts while you are a fully developed person with a complete identity. Which means you are more significant than them and they can only have power if you , who can actually hold the power , gives it to them

I felt this so much bro but just keep on pushing it’s hard I know but we are greater than the thoughts. I just want to have One day without having HOCD thoughts bro just one although I’m not thinking about it too much not doing any compulsions etc but it doesn’t go away I just don’t know anymore

But in the midst of all of this I know that my Girlfriend makes me happy because when she’s around I don’t think about it too much but They are a lot of Gay dudes in my residence never used to care about them but when I see them they just take me back to square one And I only really feel better when I’m intoxicated which is a bad thing

Maybe it will make your relationship stronger becuase you will grow and realize that's not you and you can be even more confident and open always look at the bright side becuase the issue happen okay we can't change that it happened but what you are control of is how you will act it takes time to master it but it's possible how do you think people get cured becuase they work their ass off and positive.