The whole "I do it 'cause I love you so much" excuse (a common thing that abusers say) is based on a twisted idea of love. Love isn't about control or jealousy, it's about respect.
You're allowed to be friends with anyone you want, male or female. And your boyfriend's not allowed to dictate who you can and can't talk to. The fact that he's doing this now is a sign that he might engage in even more controlling behavior in the future, like screening your calls or keeping you from talking to all of your friends.
But even if he doesn't go that far, he's already gone far enough. Get out of this relationship ASAP and hold out for a guy who treats you fairly.
If you're not sure of the best way break up with him, here's some advice.
Note: this was a real question that a real person emailed to me! (It's been edited a little for the purposes of this article.) If you want to ask me and the rest of the Teen Advice community your own question, come visit the Teen Advice forum.