I have never read such a thing to match my case.
Trust me. There have been others that have suggested the same thing to their BS. Essentially, he wants to pimp you out so that you are brought down in the mud, morally, with him. That would accomplish HIM feeling SO much better because now you're "even," while it would make you even sicker than you are after being betrayed.
Real pretty picture ... not!
Go to the I Can Relate Forum and read in the Mad Hatter's thread. You're going to see that if you held your nose and did as he requested, it would make things far, far worse.
His suggestion is that of a coward looking for a way to NOT own up to what he's done. Frankly, booting him out of the house would be my answer.