Is she open to counseling? Not MC, but an IC? Books are great but they only scratch the surface for someone who needs to go deeper.
This might be too early to suggest that. I'm reading a book Family Communication which Ad suggested and am finding it helpful. Maybe the 2 of you could take a parenting class together. Find a good one and it can be very helpful. H and I did one when our sons were not much older than your son.
I do hope for the best for you and your family.
Me 57/H 58 M36 S 2.5yrs R 12/13
Let me give up the need to know why things happen as they do. I will never know and constant wondering is constant suffering. Caroline Myss