Most Helpful Girl
It makes girls think you miss your ex. I know it really depends on your girlfriend, but I wouldn't. Would you want her going to dinner with her ex? If you haven't gone to dinner yet (it's hard to tell by what you said) invite her. Don't hang out with your ex a lot then never hang out with her and your girlfriend. That's someone that used to be treated like you treat her by you. You and your ex went on dates and kissed at one point. Some girls feel like they have "competition" with female friends, but with an ex it's someone who had one point had her spot.