Would you marry this type of man? --Pros and Cons?

Your settling for second best if you marry him. I know from experience that you are in for a lot of heartache, distrust, and worrying yourself to death wondering what he's doing behind your back. If he does this in front of you, then imaging what he's doing when you aren't there. Putting an ultimatum to him is only going to make him worse. Find someone that is more worthy of you. He has a problem that will continue, no matter what you say to him.