This is a great idea mb. Stop letting him in the house. Change the locks. Set up fixed days and times for visitation when you can have the kids ready and waiting at the door. He won't know what he is losing til it is gone!
I know how hard and scary NC is. It doesn't make sense either. When you want something, you go and get it. NOT in this case! It is hard to believe, but you are doing almost as much damage to your marriage as he is right now, by continuing to contact him. You cannot control him. You cannot reason with him. You can only feed his addiction.
There is a physical side to what you are going through. The obsession you feel is likely caused by a lack serotonin. Try uping the protein in your diet and a supplement called 5-HTP will make you feel much better.
Have you told him how painful contact is while he is seeing someone else? Have you asked him not to contact you? Have you put it in writing so he can refer back to it? Make it very clear you want your marriage but that there isn't a marriage with the way things are now.
"If you strike me down, I will become more powerful than you can possibly imagine!" 1st thread