You sound liek you are pulling it together, girl!!!
My H was the same way, being hurtful and getting stuff for the OW and not his own kids. They don't care!
I am the same way, you mess with my kids, I will get you!!
You are doing just like I did, I started taking care of everytrhing myself and just left my H out of the loop. It was better for me. Another thing, you are the sane one!! LOL