The baby years destroyed us. Babies don't come with instructions but there are no instructions for how to handle your marriage when you have a baby.
We had (have?) a very difficult kid. She still doesn't sleep through the night (major sleep issues since birth, we were up last night at 3:30 - 5:00 am in fact). Once we decided for me to SAH (which was very much a mutual decision) he felt a lot of pressure to provide which to him meant disappearing completely and it got progressively worse. The stress and resentment built and built and built. It got ugly.
Wow, like how I go off on my stuff right in the middle of your stuff? I'm supposed to be working on empathy. How am I doing? Oy vey.
I think it would be good to respond in person if you're going to see him. That way he can see you smile.