Castrated by the Fiancé (Forbidden Fantasies)

My fiancé caught me cheating, so now she's threatening to call off our wedding. My fling with that girl in the office was just that, a one-off bad decision made in a moment of weakness. I love my fiancé, I want to marry her, so I tell her I'll do anything to keep her and prove I'll be loyal only to her once we're husband and wife.

So what does she ask for?

My fucking balls. My literal fucking testicles. She won't marry me unless I let her castrate me, and I love her so much that I say yes.

What the fuck have I just agreed to?