“but I guess that’s truly not my responsibility to deal with those feelings of failure and loss he’s worried of?”

Quoted for truth.

He’s not handling this in a mature way, and dragging this out will make things worse. The longer you stay in this situation, the more it will damage your view of him, his view of you, and the emotional tranquillity of your kids. You need to separate, and he needs to get a grip.

And let’s say this again: “that’s truly not my responsibility to deal with those feelings of failure and loss he’s worried of.”

This is really tough and I wish the both of you pull through with some respect and friendly feeling towards each other. But I think a clean break is the best way to get there.