I must be the only woman on earth who doesn't think this is funny

Someone obviously trying to get the husband caught so the wife will be out of the picture.

What he’s saying is exactly what he said, and exactly what you quoted him as saying - that there is a difference between a woman hitting a man and a man hitting a woman. He said nothing to indicate that domestic violence against a man is OK.

He said that he ‘sees it differently’ because she’s a woman in response to me saying that she is a terrible person for assaulting her partner, which I take as him saying that because of her gender she is not actually a terrible person and that my opinion of her is too extreme. He also went on to argue that what she did is OK in the context of being angry, and that we shouldn’t judge her character for beating her partner. He most certainly DID say something to indicate that domestic violence against a man and/or when angry is OK. Maybe he didn’t mean it that way, in which case he can clarify.

It’s kind of depressing, especially when she mentions their sex life.

It’s funny - what’s funny is that the purported letter is a recycle from ages ago.
I haven’t checked Snopes, but this ‘hilarious note from the spurned wife’ strikes me as something I saw back in the 70s or 80’s.