I get the message, but I guess I just felt that realistically the JGL character as drawn would have had to pogo on more on himself and the loose ladies before he reached the conclusion he did. Perhaps we are supposed to believe he is ultimately more of a romantic and mature than I would assume.
Lastly I guess I felt mislead by the marketing, which promised an independent movie with wild irresponsible entertainment and ended up following the usual accepted Hollywood conventional path with the mild twist of the age differences of the protagonists, which was played down somewhat. I.e. It didn't ultimately end up being the fun comedy it was billed as. I guess that to me was the biggest disappointment.