It is really important that you find a C for D11 and D8. They are both wonderful girls, but as this continues, even after the divorce, they are going to feel a lot of guilt and anger so they need to have someone to talk to who will help them with this. It would also probably be beneficial for you to see a C too. STBXW should as well, but you can't control her, you can only control you. It is not that you need it, but going to the same C as the girls to help yourself and also learn how to help the girls is important.
I know the older a child is when a D happens, the more they feel it is their fault. You have to make sure that they don't feel this way and also to make sure they work through their issues so they don't end up in bad relationships as they get older and D11 is right around the corner from boyfriends.
You are doing great with them, but you may not be able to help them as much as someone who is not in the middle of it. Really think about it and you may have to talk to STBXW about it, but it is definitely something that will help at least the 3 of you.
Me29 S3 H left 4/1/09 I file 8/2/10 Divorce final 5/17/11 1st http://www.tinyurl.com/25lhu52 2nd http://www.tinyurl.com/2c35ueg 3rd http://www.tinyurl.com/322yk89
