When you start worrying about what she's doing with whom, then you start a cycle that continues, and the more she sees other guys, the more you'll feel jealous and insecure about it.
As someone else said, you need to feel secure in yourself. You are the best you can be, and always trying to be better (if you aren't, then you better start working at it!). If this isn't good enough for her and she finds another man, then so be it.
YOU'RE NOT PERFECT FOR EVERY WOMAN.
If she finds someone better than you, it doesn't matter, because there's other women out there who will appreciate you more than she did. And to think that you have to prevent her from seeing other men in order to keep the competition away from her, just makes you out to be extremely insecure. If you think you've got flaws, work on eliminating them. It's better than preventing her from seeing other men who might have less flaws than you.
And don't try to tell me that your feelings are based on something different, because you'd be lying to us and to yourself.
Controlling a woman's life and preventing her from seeing other women is simply a sign you're insecure.
And every single person who says they should dump the woman because she's got male friends is also showing they're insecure. Small children pretending to be men and unable to truly hack it.
Grow up and feel secure in yourself. You don't need this woman, and while you might like her and appreciate her company, she's not the reason you exist. You don't need her, and if she chooses someone else, that's her choice.
Be the best you can be, so you increase the likelihood of her choosing you.
I've been seeing a girl a month now, and I feel really good about her and what's been developing between us. She's been seeing other guys who have been friends or ex's. I encouraged her to still see them, saying that I'm not here to disrupt or take her away from the life that she enjoys having. She slept with her ex 2 weeks ago, and lied to me about it, having me think that nothing happened. A week ago she told me the truth, that she'd slept with him and she felt horrified by it because she was starting to feel strongly for me. I thanked her for her honesty and told her that I forgive her. I told her that her telling me this, and with how things were developing between us, meant that we were becoming exclusive with each other. She agreed. I told her she can still see him if she wants to, but if she ever slept with him again, I'd leave her, and she's the one who has to make the choice about who she wants to be with.
Since then, she's 'dumped' him, not seeing him at all (they've been friends for many years), constantly lets me know about her movements and the people she spends time with, and has become much closer to me. As far as I'm concerned, this woman is awesome, and I'm looking forward to seeing where her and I go in the future.
Without insecurity you have strength. With strength, you have power. These qualities are attractive to a woman.
I've seen her ex as being an AFC, sending her texts about how much he cares about her, and telling her about the mistake he made and how he wants her back. She's told me about this, and shown me the text messages. I know she wants me, wants me to trust her, and is doing the best she can do to keep me.
By letting your love interest do whatever she needs to do, without controlling her or showing your own insecurity, you prove yourself to be the best catch she can possibly find, and isn't that ultimately what we're all after? A woman who can't get enough of us?
Anything else just makes you an AFC, even if you think you're a DJ.