PG doesn't mean it's okay
This movie is well done for the most part, funny and engaging ... to a point. The main character, Reed Fish, wavers between two women throughout - and simply demonstrates that he loves himself more than either of them.
We the viewers are supposed to believe that Reed is misunderstood and has, "always tried to be what others expect," while at a more basic level he is simply an irresponsible and self-centered young man, desperate enough to sleep with the prospect he doesn't like so much just so he can keep her on a string (in case the other girl doesn't work out).
Spoiler warning! Do not read ahead if you intend to watch the show ...
The most irritating part is the way the female characters turn around and act as though Reed has done the right thing in the end. Ugh. NOT such a good object lesson, since everything works out for Reed.