In my opinion if you have to force people to do something, it’s just not worth the battle. If you have to force your partner not to see other people, is it even worth it? And what would stop him from doing it secretly?

People are who they are unless they are very young and still growing. If he is capable of secretly maintaining an affair for several years and is capable of carrying on with the person after he was caught, that is who he is at his core. Several years of affair isn’t something you can call momentary laps of judgment and a mistake. It’s not one drunken night stand. It took a lot of effort to keep it going and takes effort to keep going with it now!

We aren’t talking about asking him to pick his socks of the floor and put them in a hamper. We are talking about fundamental issue here. You can’t change people or make them do stuff or care for you the way you think is right.