Quick, destroy the letter and present it to Cadence as an orphan randomly left on the castle steps. I bet she’d take it in. It can grow up to be the hero that slays his monstrous mother, there are plenty of stores like that.
@Timberwolf
And possibly help him find a support group or something. I’d imagine that if something that was wearing your face took advantage of your spouse, that’s not an experience you’d want them getting flashbacks of, for both your sakes.
Given that he (1) thought Chrysalis was Cadance, and (2) was mind-zonked on evil magic at the time, it was a clear case of rape. I’m pretty sure Cadance will forgive him.