Read Why Sex Does Not Keep A Man

The fact that you've found a man you are attracted to or that you think you love doesn't mean that you should try to get him by luring him to have sex with you.
Giving him your body won't keep him. It's funny how girls go `who was that girl I saw you with today?' How can you be asking a guy that
never asked you out before you willingly gave him sex such a question?

If you like a guy (maybe because he is cute, rich, physically attractive or for whatever reason) try as much as possible to keep your dignity as a woman. Make friends with him, get close to him, make him notice that you have an interest in him and try as much as possible to be yourself all the time. Don't try to be what you are not because that's a bad thing to do. Yes, men are attracted by what they see but they are kept by what they feel (love)

So whatever you do, never try to use sex to KEEP a man.