Golly, breadstick ... I hope you had your tin hat ready for the barrage of posts telling you that you're unreasonable, selfish, insecure and overbearing.
However ... I know where you're coming from. All my regular friends are girls, and all my BF's regular friends are guys. If he was having coffee with a girl from work, during the day, that would be fine. But if he arranged to meet her to go shopping, I'd think it was a bit weird (unless he needed her to help him buy a really expensive present for me, LOL).