Why would investing in someone but yourself require giving up sex with others? That dichotomy between the unattached bachelor and the loving monogamous spouse seems to be just another of those taboos.
I was merely stating that committing sexually can in fact be a good thing, and that the parent comment cannot speak for everyone.
Because more often than not that someone you've invested in is hurt by your casual sex with others.
Why would be compartmentalizing the casual sex more "rational" than not?