Most Helpful Guy
it sounds to me like you guys really need therapy/relationship counseling. there are a lot of issues at work here but I think that deep down there is still a lot of love
the death of a child is almost always very traumatic for parents. it's hard to look at the other person and not be reminded of the experience even when on the surface you may be over the grief. and that grief and trauma can really seep into all aspects of the relationship.
again it does sound like there is still love between the two of you. I think a relationship counselor could help you two at least get to a place where you may be able to see if the relationship is salvageable and how to go about doing so