Q&A Could You Please Explain Dissociation and How It Can Cause and Affect People in Affairs?

The descriptions I’ve read have really resonated for both me and my husband – the memory loss both about his affair and other things, the difficulty functioning, iron compartmentalization, snapping out of it immediately on D-Day, the fact that when I ask him questions he says it is like a different person did those things... What are the reasons that someone would dissociate to the extent of having an affair? Is it always trauma related? I am concerned that there’s some trauma in my husband's past that he hasn't told me about - perhaps that he doesn't even remember. He has said repeatedly that he realizes now he has been an island his whole life and never really let anyone in. He is opening up now but when I ask about his childhood it’s the only time he still gets very guarded and defensive – as if I am trying to blame his parents when I’m really just looking for info on childhood wounds we all have even in the best circumstances. If anything he was coddled too much as an only child and the reality check of real life has hit him and his self-esteem hard. Can being a "golden child" cause trauma in some way that would result in this kind of behavior? As a way of coping with disappointments about life and himself? Are there any resources you recommend for looking into this more?