HAS ANYONE EVER FELT THIS PLS HELP!?!?

I know it sounds stupid but, I don't want to cheat on my bf but in my dreams sometimes I do and it scares me to think of losing him. And he loves me so much and so do I but it scares me maybe one day I'll fall for someone else and either... Leave the guy I've been with for 8 months and be with a guy that might or might not make me happy. All because I don't want to miss out on something and I never thought someone could love me but now I do believe.

All I'm saying I don't know what the fuck I'm doing, and have a case of FOMO but don't want to lose the guy I love.

I know this is stupid but I was hoping I could get some advice in stopping this feeling or figuring it out.

Or is there anyone else out there that has felt this pls?!?!?! Help!?!?!