Is this messed up for him to do or is it nothing to care about?

It's not necessarily wrong. He could of got up and went to facebook and just saw something she wrote and checked it out. It sucks that it was an ex girlfriend, but sometimes things just catch your eye.Or maybe she happened to be in a dream and so he got up to see what was going on in her life. If he really did get up with the intentions to go look at her page and leave you in bed then it is kind of wrong. Not really bad, but something you should ask him about. If they were together that long, there is a chance there is still a connection or feelings for her. She might of been his first love, some people say you never really truly fully get over that first love. Sometimes the what could of been might linger in his head, but he is with you. And if you guys live together, well for me, that's a big step of commitment. I don't think it's that wrong, but that's my opinion.