She lost a bet...

Ah of course, this makes perfect sense given that your penis is so small and you therefore lack the confidence to approach women.

You're so pathetic that your current girlfriend lost a bet and had to start going out with you. This despite the fact that you are obviously some sort of sheepish wimp who lacks any social wherewithal.

Despite your average looks, women have never typically given you the time of day. This is likely due to your soul being irreparably damaged by your tragic case of "small-penis-have".

Women smell your weakness even if they don't really understand why. Some of them seem to even naturally assume you must have a small dick. That or you are some sort of autistic or homosexual. None of that matters now. Because somehow a modestly attractive woman who takes bets too seriously is now romantically joined with you.

Little does she know how little the little she doesn't know is...