Also, I can’t figure out what exactly the OP means by “one of my neighbors sounding distressed”. Does he mean that he knows it was this particular female neighbor, or that it could have been either of them?
And yup, put me down on the side of “violence against men is no more acceptable or ignorable than violence against women”. But if all you heard was the sound of one slap and you have no actual knowledge of who threw it or where it landed, then I don’t think there’s any reasonable action you can take here other than perhaps to be more vigilant about this possibly abusive situation in future.
(And given how little actual knowledge you’ve turned out to have about this incident, your thread title is unjustifiably clickbaity IMHO.)
Sure, it’s difficult to read his OP, it doesn’t quite fit together well. And if the noise kept up he’d be entitled to call the police even if there was no indication of violence.
I agree that the OP made a mightly leap to a questionable conclusion.
I once had an apartment with a very thin wall and a young couple on the other side. They had very loud fights and very loud sex, with one often leading directly to the other. Sometimes it sounded pretty violent, but it would have been insane to guess when “domestic violence” might have been happening, if ever.
Btw, when I saw them outside they just seemed like two sweet kids.