Boundaries, definitely. Not only to protect me from his poor behaviour, and give him the respect as an adult to deal with his own emotions and issues and wants and needs - whether or not that felt like abandonment at the time - but it also helped me refocus my mind on what I wanted and needed in any given moment, and how I could give that to myself. It stopped me controlling and manipulating others to get my needs met, and helped me concentrate on my own needs.
All of this is essential in sex too, of course. So I think it is an indirect way of also working on the SSM. And nobody wants to have sex with a nag or a whiner or a control freak, so I do think good clear and consistently applied boundaries also makes a person more attractive.
In the moments where you are triggered, do you know what you want from your H, May? (This is some boundaries work - figuring out what you need, and how to give it to yourself or ask someone else for it, without demanding). Do you know what would help in those moments? Have you told your H what you would like from him, and are you gracious if from time to time he can't give it?
I don't have those moments any more, but when I did, my H would often experience them as me turning away and judging him or criticising him out of the blue. He was afraid that was going to be the rest of his life - me bringing up the worst thing he ever did and making him feel terrible for it whenever I felt like it. I don't think we really moved forwards and past that (and it doesn't happen any more) until I could self-soothe a bit more, and ask him for what I needed in the moment in non-blaming language, and he could respond without defending the infidelity or himself. I guess if your H experiences you being triggered as you 'turning away' that 'turning away' could also trigger him (do you see what I mean? He might be doing something entirely different - and I do think as well as all of this he's an emotionally immature entitled so and so, but you've got to work with what you've got and this man is who you choose today). I think if you consider he might be extraordinarily sensitive to signs of you 'turning away' and likely to misinterpret any quietness or distress from you as a turning-away, then maybe explaining to him what is going on with you and what you want in that moment might help.