Most Helpful Girl
Because you're looking at the wrong women. Think about all your past relationships and watch for patterns that you find in the unpleasant ones, then avoid those in the future.
Most Helpful Guy
Women don't fall in love with people, they fall in love with the idea of having a partner that they are just barely undeserving of.
It is a highly conditional attraction dependent on the perceived quality of her partner that has to be carefully maintained by the male throughout the entire course of the relationship by repeated displays of superiority.
As such they struggle with being loyal, because the inherent nature of their attraction towards men is incompatible with the concept of loyalty.