Dictionary meaning of misogynist:
a person who dislikes, despises, or is strongly prejudiced against women.
"a bachelor and renowned misogynist"
He clearly thinks that you think it’s ok to shag around or something, and therefore you must have encouraged her, which is why he’s calling you a slag, because he thinks you condone her behaviour. Even though you told him you told her not to. He has to blame you coz it can’t be her choice to do that as she was a happy housewife until you got involved type thing.
He’s just lashing out because he is hurt. It’s easier to blame you for her behaviour than to blame himself for anything that caused her to leave him.
It would be better to tell her not to tell you what he says about you. If she keeps his comments to herself then you won’t get hurt by them.
No reason why you can’t still be friends with her. She’s not said anything bad to you has she? It’s just him and her reporting to you what he said? You feeling piggy in the middle.
Has she actually moved out? If so you won’t see him again as she will cut ties. So you won’t be in the middle.
It’s always better to be alone yourself between dating/marriage etc. She should have left him and then dated someone else. Sometimes the grass is greener. Only it’s not. So I hope she has made a good choice.