Hey, if you're living with someone, you're an idiot to have an affair. And even stupider to have an affair that anyone with 50 IQ knows will be discovered.
It's a combination of self-preservation, common sense and common decency not to do that. Fuck around all you want if you aren't living with someone.
I think it's more dangerous to fuck around when you are living someone than if you are married. If you're married, it's a real pain in the ass to get divorced. Thus you are more likely to get a second chance.
How the fuck did this guy get into law school if he wasn't smart enough to get his name on the lease? If he was living with her, it should have been a no brainer. Then she wouldn't have been able to kick him out without leaving herself.