Hate to say it, but if you don't cut him a little of slack and vice versa, you're not going to successfully piece.
I think if you were to confront him with this message and he were to clarify what happened, you wouldn't believe him no matter what he says.
"If I am expected to just look the other way because it's too hard for him then I am not cut out for this."
You'll definitely not be looking the other way. Our sitchs are such that we get paranoid about our Ss. Take me for example. My W had a strong EA with her boss. Strong enough to want to leave our M and kids for this married guy twice her age. Today she doesn't work directly with him, but still sees him everyday.
Now she has told me that she has not feelings for him. I know that's not true because quite frankly that's not human. We don't automatically forget those things. But do I trust her when she says she keeps it professional and doesn't do the things she did before with him at work? Absolutely until I discover otherwise. I have detached enough that I trust and love her, but if I find any indiscretion, she's going to find her ass on the street.
My W has NEVER apologized for what she did and not shown any remorse. But her actions have spoken louder than words.
Your exBF has actually said he's going to give it a chance which is way more than alot of our WASs have done. Give it a chance.
The paranoid feelings don't go away quickly. And trust is something that is earned definitely. You can try easing up a little and see what happens. Just my 2 cents. : )
M-43 W-40 2D - 9 and 5
Emotion, yet peace. Ignorance, yet knowledge. Passion, yet serenity. Chaos, yet harmony. Death, yet a new life.