I don't understand

I don't understand. I got a call from my friend a few minutes ago. She was sitting at a family dinner when her husband got a call. She went to get his phone for him and it said, "Jill's phone." She handed the phone to him and he walked outside to answer it. When the in-laws had left for the evening, she asked him who Jill was. He said, "What do you want me to say?"

This is not the first time that this has happened. The last time he was having an affair with a woman that he worked with, and this time it is the same situation, different job, different girl. The last time they separated for a while, but she forgave him and came back. This time she may not forgive.

I don't understand. Why would you do that to your wife and two children? Three people who desperately love you and want to be with you and still you look for a relationship outside. And to be completely honest, my friend is hot. She's beautiful even after having two children. She eats well, exercises and still buys the smallest size on the rack. She gives him everything a man could want.

And yet he looks outside his house. His family life sucked so I'm sure that's part of it, but it's no excuse for the way he is treating her or treating his children. I truly believe that he still loves her and his children, but he's stupid. Stupid. He's an ignorant a**. I will not call him that to his face or anywhere else - except for here - out of respect for his wife and children, but that's how I feel. He's an a**. He doesn't realize that he has everything right now.

She said he started crying after they discussed him moving out of the house. He had all the power in the world to avoid those tears. If he had focused on the family that he had instead of looking elsewhere then there would be no tears.

So what is the right thing to do? Do you stay in the marriage because it's a marriage? Or do you walk away because you have to respect yourself and teach your children to demand respect from the people in their lives? I'm not a big fan of divorce, but I just can't believe that the right thing to do in this case would be to stay in a relationship where you don't trust the person that you are with and he continues to throw it in your face and disrespect you.

And now after almost ten years of marriage and two children, my friend is likely to be a single mother.

I don't understand. Don't understand.