I need help! my fiance keeps telling me I have mental issues.... I have 100% no trust in him for what he has done to me a couple months ago. here's what happened.....

I had that feeling like I needed to check his email. so I did and this son of a bitch has a picture of some UGLY, GRENUDA, FAT chick in his email THAT HE SENT TO HIMSELF!!!!!!! mind you it was 4 days before my birthday. I did all my research and figured out the girls number, so I texted her. she didmt want to tell me anything. she told me that he was "trying" to cheat. which I don't understand. I don't know if they hung out behind my back or wtf was going on between the two of them.

AND THEN! comes to find out it was the receptionist that used to work with him. I was devastated. i know I am beautiful and i know my worth. I just don't get why he would talk to another girl behind my back. I work 3 days a week and when I am off, I clean and make sure dinner is on the table for him the minute he walks into the door. I don't know what else I need to do to satisfy him and to make sure he doesn't do shit like this.

back to the point....

right now he's in Nebraska for work and it always comes to my mind that he's talking to another girl behind my back to keep him company. I ask him just to reassure myself and he always tells me I have mental issues, personal problems and that I'm not happy with him since I can't "get over the past"

am I crazy or is he being controlling and a fucking douche? or am I really crazy? I've made it clear to myself that I'm not crazy. but maybe I am.

I need some thoughts. I have NOBODY to talk to about my relationship because now days its hard to trust anyone with my personal business.