Sex isn't just for procreation - it also serves a social-bonding function.
You heard me - sex is for social-bonding, too.
(That doesn't mean everyone must go about being wildly sexually promiscuous with everyone they're friends with - far from that.)
It just means that sex, as part of the continuum of body-based affectionate behaviors (from brief affectionate touches, to hugs, to chaste cheek kisses, to co-grooming like hair-brushing, to massages, and so on, on up to yes, the genitals...isn't just for making new humans.
And it never was.
That's what makes the anti-contraception-ers so sad.
I suspect that what's really behind their zeal is a form of self-hatred in which they think that neither they...nor anyone else...deserves to feel good.