Casual sex and guilt

My thinking is:

Sex as an activity, and the parts involved (genitals) are something not shared by society; they are very, very personal parts of ourselves. If someone has sex so casually, I often feel that it (1) cheapens the overall meaning of their intimacy if they've shared it so easily. And in love, a dignified intimacy is something worth cherishing. Not saying it's right, but that's my thinking on the matter.