I'm sorry to hear about D6 and I agree that just becuz S9 doesn't express his feelings, doesn't mean he's not hurting as well. You were absolutely right in stepping in and making your W see the reality of her actions. How dare she blame you or your Mom but then again, nothing is her fault. I just don't get it.
I am also glad that you both agree on taking the kids to IC. This may just be the wake up call your W needs, if not, at least, the kids will get some help in dealing with this. If you and your W can't live together, at least be the best co-parents for your kids. This would be a step in the right direction regardless if you get back together or not.
Being a dad for 100% of the 40% of the time you have them is more than anyone can ask for. You ARE a wonderful dad and don't let her ever cross that line.