ML, I do feel for your X's aunt but perhaps he will turn a corner at some point.
Wifey or not, it is good that your S is re-forming a relationship w/X. I believe abandonment issues are difficult enough but your S was at a particularly impressionable age, it seemed.
I can say that it is difficult to see children form R with OP, but it is better that they have relationship w/X.
M: 16 years Bomb 4/07 OW 20s long gone Divorced 11/09 I remarried New Guy Cooperative r w/X regarding D