I have seen her since my previous last post. I spelt it out to her. She was told very clearly and asked why I hadn’t gone to police if it was true. I explained the reasons calmly why not. Her response was to announce their relationship on Facebook and do matching his and her profile pics.
He's prepped her, of course.
He knew there was a possibility of you telling her. (He also knew there was a possibility of you reporting him to the police, but he's breathed a sigh of relief and is getting more confident and trying to ree you back as a fuck buddy (for his abusive style of fuck buddy-ing) now that a report hadn't happened in months, he thinks of it hasn't by now, it won't; and no doubt thinks the longer after the assault it's reported, the less likely it is to be prosecuted etc.).
He prepped her and told her you might accuse him of rape/sexual assault because you are any combo of jealous, rejected, bitter, angry, deluded, unstable, obsessive, vengeful etc etc.
He's probably told her you wanted to leave your h for him, and he wasn't interested in that; wasnt interested in a full relationship etc. ....... and so you're hurt, angry, bitter, intensely jealous of his relationship with her, and would do/say anything to try to break them up.
She's believed him (and of course coincides neatly with her clear desire not to end a relationship in which she's apparently quite heavily invested) hence her public statement/reaffirmation of their relationship relationship.
You've told her, she's a lost cause, she'll probably realise what hes like - eventually, but what else can you do.
It's not your fault and it's wholly understandable but you not reporting him has played into her being able to believe him.
(Also you being married and having had an affair with him makes you look potentially dishonest/disordered; another reason she might believe his lies).