Fig, you pose an interesting question, and one I asked myself today actually.
If I were really honest and really looking at things, I'd say it's my anger coming out, which stems from feeling inadequate as a wife. Why else would my H look outside of our M if I was good enough?
I am very angry at myself that I chose to love someone who turned out to be this kind of person. If no one else protects my heart, I have to, and I feel like I let my guard down, and got hurt because of it.
It's something I'm trying to work through. I honestly don't believe he's making his way back. Maybe that is my cynical mind working, but I really don't trust anything he does or says right now. And that trust issue always comes out as anger in our interactions.