I am very sorry that your family has suffered so much from this relationship. It's a shame that there are some partners that find more satisfaction in the company of others. I would distance myself from him emotionally, physically and verbally. Cut his calls short and maintain guidelines that do nor encourage information being shared or your being proud of him. It is very unrealistic to expect any such reactions from you. You owe it to you and your children to be realist - interact with your children but not you. He can interact with your children and not as a couple. When he calls, make sure you keep it light and brief. Also encourage less contact by informing him that you will not be available at certain times. This will encourage him to call less.
As far as hope, there is always hope. But you can't be distant and hold out hope. One is inconsistent with the other. If you want to discourage communication then you have to be emotionally distant. Don't do anything that encourages behavior you wdemand respect and not tolerate disrespect to maintain a relationship especially because maybe it's comfortable.