Hmm...I have this problem too, except I've been going out with my boyfriend for over two years. We just had a big fight about this yesterday actually - he's at uni and I'm on a gap year. I don't actually like him talking to any other girls, which I know is ridiciulous and there is no way that I have any right to stop him doing that, and I've tried really really hard not to mind his female friends at uni (even though they've made absolutely no effort to talk to me when I visit, even going so far as to blank me whenever we bump into each other) but yesterday he was in some girl's room 'choosing clothes for a cross dressing bop' and getting changed in front of her! I phoned him up in the middle of it all and he was like desperate to get off the phone, and I could hear her giggling inanely in the background trying to get to me. It really pissed me off, so much so that I threw a massive strop and he spent two hours travelling home to visit me.
I'm trying but it's so hard! Grr. He says it hurts him that I think he would cheat on me, but I don't think that. I think I'm jealous that these people I don't like and think are quite boring get to spend way more time with him than me atm. I sympathise with you OP - do you like your boyfriend's female friends? How is he with your male friends? xx