I know other people have said you shouldn't try to get with other people's boyfriends, and they're right. It's an unfair thing to do, and when you finally settle down with someone you would be gutted if another girl tried to do that to you.
You need to address your issues with how you feel about yourself. If you feel as though you "need" to try to get with people to feel wanted, then this is a severe issue for you I'm afraid. I know what it feels like to need to be wanted. I also understand how good you can feel to get attention from men - even if it's not the men you should be even thinking about - when everything else makes you feel alone.
But I promise you, enabling men to cheat will not make you any more popular, and even if you do end up with one of these men, if they cheated to get with you, they'll cheat on you, too.
Stop trying to get with people. Address your own personal issues, and see a counsellor about how you feel. You can never be comfortable in a relationship until you're comfortable with yourself.