<human>: Can you give me the gist of the text in a nutshell?

It all started with a coworker. He told me she had a thing for him and tried to make passes at him a couple of times. The last straw was when I found on his cell phone deleted messages of him inviting her to a bar that he and his friend went to. I know that's not enough to break up with him but damn, was I ready. What hurt was the fact that we had gotten into a HUGE fight the night before and I felt he was running to her with our problems. He later told me that they had developed a friendship based on their mutual conflicts with their SO. I felt that he emotionally cheated on us and that had he been given further encouragement by her, he probably would've developed feelings for her. What really pissed me off was that he lied to me about their friendship. They would drink together alone during their break and have drinks with other coworkers after work. I told him to break all contact with her after I found out he was trying to invite her that night at the bar. Well, he told me he would and didn't. I found out because this girl kept sending him texts afterward. So I took matters into my own hands and called her. I was very respectful and told her that I wasn't comfortable with their friendship and that I'd like for her to place herself in my shoes. She said she understood and that she would've done the same. Now that that's over, I still find that he looks her up still. I have had issues with infidelity before in a previous very abusive relationship. My ex displayed the same behaviors and eventually ended up cheating on me physically several times with his coworkers. I don't want that to happen to me again but I feel I'm being unreasonable with my current SO. How am I supposed to let this go? How unreasonable do you guys think I'm being? Please, I need a reality check, I'm harming my relationship over nothing.
<bot>: I caught my boyfriend lying about his state of friendship with a coworker and I can't get over it. I feel I'm sabotaging my relationship over nothing. Help me gain perspective and control over my emotions again.