Girls like nice guys, they just get bored. Honestly, no offense to most women, but they kind of suck at entertaining themselves.
We boys can get some food, a good video game/movie, and we're set. Women need more. Don't worry. If you have no trouble getting a girl, then you're fine... maintaining a girl is far easier. Just do more social/public stuff with her, that's all that should be necessary; though it does depend on the girl.
Your best bet is to find a girl that shares a lot of interests in hobbies and activities, so the both of you can have fun together and it's truly mutual.
