The fact that she would take his phone and change settings on it without consulting her bf could indicate that she is on the controlling side. Also, she says she was just changing his background. How do we know she wasn't trying to be a snoop. I'd be willing to bet that 99% of these posts are embellished in some way. Also, with a post like this there is a very good chance it's being told in a way that makes the poster sound faultless. I'm not condoning the fact that he had naked pics of his gf's sister, he's still a douche for that. I'm just saying, more often than not, both parties share the blame in an infidelity. Believe me, I've witnessed enough to know. It makes me that much prouder that I can say neither me nor my wife have ever had an affair.

Sorry but no matter how controlling a person is or how poorly the relationship is going you NEVER cheat, EVER. You leave if there is a problem you cannot solve, then you can be with someone else. How is this such a difficult concept for most people?

She wasn't snooping. she was trying to do something that she probably considered cute by changing the wallpaper. I wouldn't really call that snooping.

72 how is that cute?

^^ This. The amount of distrust in most relationships is ridiculous.

oh but they are...

....The sister is 18. That's neither illegal nor child pornography. At least not in most countries you see as post locations on FML.