Universal truth? Do you say that with a straight face?
Come now, don't tell me that that statement appearing in one of
my posts surprises you, given what I've posted before. (In other words, yes, I say it with a straight face.)
However, your sarcasm in the next paragraph misconstrues what I said. I'm not going to bother to say it again, so if you want to understand (and I think you don't) you can go back and read again what I said.
To answer your "serious" question with what someone already said in this thread earlier, though phrased differently, if person A is such an awesome lover that everyone he sleeps with compares their future partners with him and they don't measure up, making them unhappy whereas otherwise they would have been perfectly satisfied with the sexual ability of the person they eventually marry (who is more compatible with them in every other way than person A is): That's hurt.
The point is that sex is a serious issue with lasting consequences you just can't guess at in the moment. It has emotional and social effects on your partner that you can't predict. Now, in any sexual relationship where both parties have already slept around a lot, I think the fact that they're having sex probably won't have any particularly profound effect compared to any of the previous encounters, but the initial ones can set the tone for the rest of their life. See, for example, girls who are sexually abused growing up and can never thereafter form a healthy sexual attachment. It's just common sense that even in non-abuse situations someone who gains their sexual experience by having sex with a bunch of different people will become imprinted with that pattern and will have difficulty moving to a monogamous relationship that lasts decades and decades. Now, if you think extramarital sex is A-OK or never ever intend to get married and only have sex with people who never intend to get married, then maybe promiscuity will work for you, but it's not ideal and it will not contribute to the advancement of society.
Karen (my wife reading over my shoulder) says she has read studies (such as the one referred to
here) where women on college campuses who are pushed to have non-committal sex/"hooking up" (by peers whether male or female or by the media, etc.) are finding that they have real serious emotional consequences and the girl can't figure out why, because she has no conscious emotional investment in this guy—she just slept with him to gratify her sexual needs. But the hormones released by a woman's body during sex make the woman bond with the man, and if either the woman or the man takes off after that, the woman will feel like she's leaving a piece of herself behind.
