Same thing happened to my brother. Started reading JP about a year ago and now constantly berates feminism and women - tho he says he loves women (my mum, his GF, and me).
I don't think JP is to blame, tho is a gateway to allowing men to express their misogynist traits. My brother has always been miogynist (like my dad), it's just he was never interested in the philosophy or politics around MRA until now. Or had the language to talk about it. Now he does.
In a way its a good thing, because he can express who he is and what he thinks precisely. I guess it's the same with your DP. He probably, like my DB had misogynist tendencies, but now can express and justify them.
When people show you who they are, believe them.
Does he have a sister? Perhaps you could ask her? If my "SIL" (they arent married, just been together for ages) asked me, then I would be willing to divulge and give advice.
My advice would be be. He's still the same person, but he's showing you who he is. What you do with that information is your call. If you can live with that attitude (some women don't care) then do it. If you can't (and I wouldn't) then don't.
Problem is with blokes like my brother and your DP the political isn't personal, so when they talk nonsense about "women acting victims" they don't realise how hurtful and insulting they are being.