I said it in another thread somewhere -- hot chicks are not single for very long. I don't know if it's some sort of social pressure like "wow all my friends have boyfriends and I'm single, what's wrong with me?" -- if it's something like that or whatever the case may be but the men I know, when they're single; that can mean years. With hot chicks, it's weeks. They find new dick whenever they feel like they need new dick. The ease of which women can find sex is both comically sad and hilarious but that's the marketplace I guess.
Anyway, you just have to catch them in that small window between exclusive relationships or dudes that they're banging hoping it will lead to an exclusive relationship. When they say it's a numbers game, it really is. Keep on approaching, you're bound to find one that's single. Outside of her having a boyfriend and willing to cheat, and you being willing to fill that role, there's not much more you can do.
Anyway, you just have to catch them in that small window between exclusive relationships or dudes that they're banging hoping it will lead to an exclusive relationship. When they say it's a numbers game, it really is. Keep on approaching, you're bound to find one that's single. Outside of her having a boyfriend and willing to cheat, and you being willing to fill that role, there's not much more you can do.