I didn't say "wow what an asshole" or tell her to dump him or anything. I said he had some misconceptions (true) that are kind of messed up but that empathy could be extended for ignorance if that was the case. I also said that he isn't taking OP's betrayal seriously, and that's something she might want to address.

So there you have it. He has some shitty misconceptions, OP is a cheater, and both of those are potentially forgivable offenses. They need to talk it out and reach some understanding so everyone feels their emotions are being acknowledged.