Boyfriend having female friends

I honestly cant stand the idea of my boyfriend having a female friend, and i think its because he flirted/messed around with another girl while we were dating a couple months ago and i feel like i cant let that go. Ever since that i dont allow him to text/hangout with other girls and i DONT want to be controlling over him. Any tips for me to be okay with allowing him to having female friends?? How do u girls do it? It just makes me sick thinking another girl is having fun with my bf