Donna Hanover might have been a piece of work, but most intelligent people would get a divorce before starting an affair with someone.
This is a big flaw on his part. He’s got some amazing qualities, and it’s not just the “he’s human” thing.
I don’t think most humans cheat on their spouses. Some do, and it’s not just a character flaw, it’s hurtful of other people, like their children, not to mention their spouse.