i wish i could just be happy with my partner without thinking every second of every day how i messed up and how i should just break it off even though i know that i do love them and they are the best thing to ever happen to me. why can i just be happy

i feel so bad for posting here, idk what i wamt i have so many thoughts abt the feelings i have for my bf im scared my thughts are true or that they will be true and i feel bad for feeling amd thinking this way i such a bad girlfriend, i am scared that i like other people just because i look at them or talk to them normally and i feel like a liar what cam i do to stop feeling like this i am scared

I know he’s not cheating on me. He’d never do that and, as hard as I try to tell myself “he’s proven already that he’s not” and show myself all the signs of commitment and dedication, I still have that fear. It’s eating at me and ruining my relationship. How do you guys get over this? If my brain were true he’d have been cheating on me for months in ways that aren’t even possible. It doesn’t make sense if I think about it logically but it seems like when I do, I create in my head more ways for it to be logically true. What is your advice? How can I stop self sabotaging?

I can’t stop thinking to myself “what if I don’t love her” but deep down I know I love her and that’s why I’m getting pissed off with these unwanted thoughts because it’s putting doubt in my head when in reality I love her what should I do?