No one is a perfect mom or dad. You are doing a great job of taking care of your girls. Your xh is just looking for something to stir the pot with. He's not happy w/the way things are going in his life, so he wants to share that unhappiness w/you by criticizing you. Ignore him.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.