Confused

So I have a first love that I’ve been in love with since like elementary school. It was always one sided and i decided not to put my life on hold for someone who didn’t want me. Lately he’s been on my mind a lot and idk why. I’ve been strongly considering dumping my bf and idk if it’s because of the thoughts I’ve been having. I feel like I’m somehow being unfair or betraying him. Like idk if I’m out of love or just frustrated because he’s not my first love so I want to leave him. I definitely don’t want to dump him if it’s because of the other guy cause this will probably pass (whenever I don’t think about him we’re fine). I’ve been really short with my bf as well and idk if we’re butting heads or I’m just lashing out because he’s not my first love. I get annoyed seeing his name pop up on my phone now and rarely engage in conversations. I feel bad cause it’s not really fair but I also don’t know the root of my behavior. If I’m unhappy because of the relationship or unhappy because of who my bf isn’t. Idk what to do tbh