I highly doubt it has anything to do with the manosphere and everything to do with the idiot hooking up with and getting into a relationship with a girl that was already in one. A body count of 5 is pretty low for a 21 y/o girl so hes really probably just now thinking about why the last relationship was open and concluded it was because her ex was not of size. He is probably also not of size. Either way, I dont think he sees OP as a long term option.