Casual sex is disastrous for society. You are at a high enough social strata where you are not affected, but it has decimated the inner cities. time_management wrote an excellent comment describing how monogamous relationships are key for civilization:
Even people who enjoy casual sex don't enjoy a history of casual sex in previous partners, and those who don't enjoy or do it disapprove even more. No one wants his or her kids to have a parent who slutted it up during college.
I'm all for "free love", so long as it's actually love and not lust or something worse.
