Most Helpful Guy
The guys women attract are typically players that are just looking for sex. The guys that want more in a relationship are either shy, or in a relationship most of the time so they aren't hitting on ever girl they see.
Chances are the guys you are going out with are just looking for sex, and you are giving that to them very easily. They don't see a point in taking the relationship any further because their needs are already being fulfilled. Either learn to start spotting players, or stop putting out so fast.