My mind is annoying the shit out of me.

My fiance just started working and theres this girl there. He came home telling me her full name because apparently it's on the roster that didn't bother me. However today he came home telling me her age and that she used to go to school with his brother. When I picked him up he was standing on one side of the road and he was standing on the other. I get upset and what not. He tells me that there is nothing to worry about, he doesn't talk to her and if he does it's about work blah blah blah. you know the typical guy stuff. If you only talk to her about work how do you know her age and what school she went to. Anyway he calms me down after a while. He hugs me tells me that I just need his loving. Tonight I had a dream about her and boy did I wake up wild. I want to believe him so bad but my fucking mind won't put me at rest 😡😡 I guess I'm scared of loosing him guys. I just want to believe him and not be so damn crazy haha.