No contact means no contact, no matter how innocuous Facebook really is. He needs to rebuild trust, and if what you need to do that is no contact with ex-girlfriends, then he should respect that. It just draws the process out if he drags his feet!
I've got to be honest, I would be thinking hard about changing the locks while he was out one day. He's showing a lack of respect for your feelings and your marriage that I would have a hard time justifying.