I think you still haven't broken through a vital stage to proper renewal of a relationship, HH. Still things feel furtive, cowardly, passive. You are aware that the phone is a trigger to your DH. It is a literal, physical example of someone having a private, discreet relationship with someone they can't see right under their nose. It is symbolic of your affair.
Of course you are sympathetic to him but again, here, you are framing yourself as passive and faintly victimy in this. You are suggesting very subtly and quietly that his paranoia is preventing you from now having healthy relationships with your friends. You are claiming that you do not want to tell him about sleeping with OM and the details because you don't want to hurt him.
I have no doubt these things are true but I'm afraid you might need to step up a little more and work out what actually the problem is and take responsibility for solving it.
Your DH wakes up in the night crying, he is set off by you using your phone, he is unable to ask you questions about the details because he is so pained and afraid of what he might find out.
The solution to this isn't to just say to your DH, by the way I slept with OM those last two times i met him etc etc. And the solution isn't to never speak of it again. That's safe for you because you don't want to feel bad about yourself. But it's incredibly cruel for him, to always feel he must be the one that brings it up, to live alone with it in his own head, imagining the worst, making connections suddenly and horribly.
You need to have the courage to sit down with him and say, I can feel how much this is hurting you and I feel ashamed and take responsibility for that. I think the only way we get through this is to be closer and more honest with each other, and I think if we go into a denial stage and deal with our reactions separately, we'll be putting more distance between us. I think we should have a drink and put some time aside to talk about what happened and what's happening now and you can ask me anything you want, safe in the knowledge I love you and I want to be with you and I wonder if that might help.'
As for the phone, I know most of us communicate in text a lot these days, but it is, even in friendships, a shallow, lazy, very controlling way to talk. Why not use this as an opportunity to actually engage properly with your friends and if you actually have something to say, call them in front of DH, in case of quietly texting? You might be surprised how all your relationships start improving if you approach them whole-heartedly.