I'd say he's choosing his friend over you. Neither of them seem to care about your feelings, personal boundaries, and right from wrong.

You may need to reevaluate the need to have this person in your life. I personally think he's being very disrespectful and abusive by continuing with their friendship.. it's not a friendship.

Are you able to carry on with this relationship if she's a part of his life? It doesn't sound like you can. I'd listen to your gut instincts and take care of you.