Let it go. Our WAS will do things that hurt our kids but unfortunately we need to continue to back off. I can't stand that they involve the kids this way but I have no control over it.
Thinking back on my sitch, my kids will always know he left them when I needed him the most, days before D1 was born. So when our kids have kids they will feel resentment. Hopefully they will learn to forgive WAS but that is their issue to deal with, their relationship.
M 42 H 39 T10 (-2yrs separation) S8 D5 DD 7/30/11 (EA&PA) Reconciled 6/2013 Separation in works 1/2017