<human>: Can you summarize the given text in a few sentences?

My boyfriend and I are a super team. We try super hard to communicate well, we have similar goals and we are crazy about each other. He recently picked up a new job and is working very closely with a female co-worker (similar to an apprentice type job) everyday, just them two. 
We had a rough patch around the time he picked up the new job and he was jealous of a male co-worker I hung out with, and tried to make me jealous with anecdotes about her. Well, unfortunately it worked. I'm the jealous type. 
Things are going along smoothly between us but the more he works with her, he talks about her, he texts her on days off, bought a little inside joke gift for her, gave her a pet name in his phone, and lastly, why I am here on r/relationships, he called me by her name today.  
I am really starting to not trust him, it's creeping into my daily life, I had a bad dream about them. I don't want to lose him. With my lack of trust, I feel my world is falling apart, I am starting to react to little things irrationally. More so, I am afraid of losing him to her.

Him and I have had more than one conversation about me not trusting him because of her, and he tells me I have issues and that I am acting crazy. He is insulted that I think he would be the kind of person to cheat, which makes sense.

He doesn't understand that I am seeing these actions as red-flags, despite me telling him just this. Everyone one of my boyfriends has cheated on me except for this one, he is fantastic. Why can't I just trust him and know they are just friends that are forced to work next to each other and actually get along?
<bot>: My boyfriend has a female co-worker that he talked about to make me jealous during a rough patch in our relationship. Many months have passed, he has become close with her and I have become distrusting.