I really think you need a Therapist to help you walk through all the emotions your going through and will be going through.. You will need to be able to set up very structured boundaries when it comes to him and the fact that he is going to be in your life to a degree because you have children together.

Therapy will also help you with how to talk to your children when the questions come up about why does Mom and Dad not live together etc .. Answering these questions correctly to kids is necessary so that down the road they dont have problems understanding it all.

Im sorry this has happened to you but you are a very strong person and you will find your footing and have a wonderful life despite how he has hurt you so deeply