There is, absolutely, hands-down, a universal right to sex.

Try telling homosexuals that it should be illegal for them to have sex. It used to be in many states. See how it goes when a liberal-minded guy like you tries to tell them that they don't have the right to have sex.

Everybody has the individual right to make choices regarding his or her own sex life. That's why this woman isn't required to have sex with this guy, even though they're dating. And that's why this guy isn't required to stay with her, and why lack of sex is a completely valid and legitimate reason to not date somebody.

These people have a right to make their own sexual decisions. He doesn't have a right to force her to have sex with him, and she doesn't have a right to force him to be celibate.