Back story: my ex and I broke up in December but since this is our last semester before we leave school for good there was no point in renting out a whole new place for three months. We began a weird relationship after the break up where we still have sex , help each other out and even got a puppy together. But all with the understanding that we’re single and can see other people. It’s strange we understand but it works fine for us.  Lately though he’s been telling me how he tells girls I’m just a friend living with him but doesn’t mention I sleep with him and have sex with him all the time. Normally I’d let this go but he also gone as far as sleeping with one of them and comes back and makes fun of her for her size and tried to make jokes about how she desperately wants more with him and her attempts to win him over all while he laughs about it and doesn’t understand why I get upset over that. I also talk to other males but I’m honest about my situation so that they don’t get into anything they don’t wish to and can walk away if my situation makes them uncomfortable . At times I feel like exposing him to these girls he leads and especially the ones he comes back and belittles behind their backs. Some of the things he’s said is “ this boulder keeps thinking if she offers me free stuff I’ll fuck her again” “her body is like the bottom of a snowman does she really think I’d want her that way”. It really bothers me and I’ve told him that when he puts woman down this way it makes me uncomfortable yet he still does it.Also I haven’t done it and I probably won’t because it’s not my business and not my life but I just wonder if I’d be the asshole if i did.