It's instict to feel jealous when your current mate is talking to their ex's. But this isn't something trivial that he's calling about he may feel that she's the only one that he can talk to about his real feelings and someone that knows his mother well. I don't really see why she has to go to his place for dinner, maybe they should go out somewhere public or they can just talk over the phone. The dinner thing seems a little to intimate and it will prob. drive you nuts Do you think she can be trusted? and do you think your relationship means more to her than her previous one?