If you are "friends with benefits", it means you assent to uncommitted sexual relationships. It also means you have enabled your "friend" to do whatever he wants, as well. Your question tends to indicate you still connect sexual intimacy with emotional attachment and commitment. That is a natural response, we're wired to be that way.
I would suggest you cut him off, not just sex, but the relationship. If he wants you still, then point to your hand and say " You give me a ring and never touch or want another woman, for life" and if he's unwilling, walk away and never look back.
You brought this on you by your own permission. Please stop, assess your life and your own commitment to your self, your future, your happiness, and make sure from now on, you don't set yourself up for pain.