greencar it was my previous ex who was emotionally abusive to me. When I met ex I, like you, felt I'd forgotten what the normal rules of engagement were. I'd accepted so much crap and been so ground down I was at a loss.
My way of dealing with it was to, mostly, tell him as soon as I felt able that something was wrong. He knew some of what I'd been through, and I told him I'd never risk my mental health again. It meant we had a much more open relationship, were pretty straight with each other, and I'd quickly say if I was annoyed about something.
Can you say to your dp that you just need him to be straight with you. That you can't live with trying to second guess somebody, and that you are already aware that lack of opportunity to be together may be the problem. The word that struck me in your post was that you thought he wasn't "bothered" about making it better. You have a lot to deal with, I think you deserve someone who can be straight with you and who is bothered.
purple I see your dilemma about the screen shots. Hopefully your ex will be too ashamed to tell your ds that he's seen them. They only reflect badly on him, and I doubt he'll use them as a starting point to try and repair things. I think you can only tell your son that you were concerned for him, and that his dad needed to see what his behaviour was doing to him. It's a tough one.
I left my EA relationship 14 years ago. I still found that passage from Lundy Bancroft hard to read today. There are certain threads on here that I have to ignore as I find them too triggering. At least we had no dc to tie our futures together. I desperately hope he never met anybody else after me. I secretly hope something bad befell him, and that the world is rid of him.