Human culture contains lots of incentive structures that do just that. It is often not at all necessary to invent new ones, but rather to evaluate, choose, and tweak existing ones.

I don't disagree, but I do think that the existing incentive structures surrounding sexuality are pretty damned dysfunctional. I chose the wording I did because I think there'll need to be a lot of original thought going into a better incentive structure (and because I don't think there currently exist any really good candidate solutions), but I'm not trying to imply that we need to throw out the existing culture completely.