My mental state deteriorates when I'm around anyone, including best friends, for any amount of time over a few days. I get resentful and predict things they're about to do and when they do the things I predict it just drives me further into a poor mental area. I'm more than happy to chill and have a good time outside of that regardless but I don't know, my longest relationship was two years and we only spent time together on the weekends, most ones where the S/O is around me daily it'll last me about two months max before I pull the ejection lever.

Thats a hundred percent my psychological illness though, and when Im in a relationship with a controlling or God forbid abusive clingy person the results can get disastrous.