I am not sure if you have children. But it is best if you do if you can get over it and be somewhat friendly.
My husband cheated on me and walked out too..I was mad for a awhile and then realized it was not all him. I took responsibility for some of it. I let go of the anger and we became great friends and were there for each other and our kids to try and move on in life and wished each other to be happy , because that made all of us happy..of course he still irked me sometimes..lol..but It is best to move forward and understand you are better off. Be happy , hope he is and it will all work. honestly...It doesnt hurt to have him as a friend.