I cant speak for your partner but I know a few people in my own location who does this....a couple reasons why they do this same thing is because either...

they are followers and are doing what they feel is normal "men talk" being "macho man"
they are feeling like they should fit in with others who due to the recent political changes should be making demeaning comments like this to others, may feel now that its acceptable to do this due to the new political change involves accusations of such things.

they are abuse survivors who are just acting out statements that they grew up with.

they are an abuser who has done this before

and last reason those around here in my location do this is because there is a sexual fetish where two people talk and have consented to having a BDSM / sexual abuse relationship. maybe this is his way of checking out whether you want to be the sub and him the dominant one in the relationship and whether this kind of sexual acts are things you may be interested in too.

line in the sand is that these are all just things and reasons why for those I know, to find out why your partner is saying these things you will need to ask them and let them know how this makes you feel.