Found in /r/sex: http://np.reddit.com/r/sex/comments/2abm8i/me_17_m_with_my_girlfriend_18_f_for_one_year_how/

Look, I agree that as long as your partner has a reasonable amount of partners for his/her age, there's no reason to be bothered by it. However, the 18 year old in question here has had a lot of casual sex, done drugs, and partied hard. She's slowed down, but still goes to parties.

I really, really, REALLY hate how most of the people there just brushed the guy off and blamed him for being a slut shamer and immature ( sleeping around and doing drugs seems to show maturity). Apparently for feminist legbeards, just having a standard is a fucking political statement. They say that there are no downsides to being promiscuous, and that it's natural to enjoy sex. Of course enjoying sex is natural, but hooking up with some stranger isn't.

So, here we have people defending the girl's poor choices (she's just enjoying the carousel life! You can't blame her!), while the guys's concerns are invalidated and is insulted.

I honestly think that the OP should just move on. He's too young for this type of shit.