Amanda, your ex partner is not worth the time of day - worrying about him will sap your energy, and you need it for yourself. In one way, the fact that your exdp is being so openly selfish makes it easier to despise him and cut loose. There are no mixed messages here - he is not trying to be the nice guy while stabbing you in the back.
I think you are right to say you have no plans to contact him. Stick with that. Even if he has got together with this woman again, think what a selfish and shallow man she has now.
I am glad your friend is taking you to hospital and I hope other friends rally round. Do vent on mumsnet whenever it helps, you will always find someone here to listen.
Hope wednesday goes well for you.