I think that maybe it could be good to do some focused grieving for the circumstances surrounding the abortion. That must have been so hard and I'm not surprised you want revenge.
Thing is, something you said upthread resonated with me. I've also felt recently regarding my own betrayal from someone that it isn't 'fair' that I have to do this hard emotional work.
But looked at it from a different point of view...I'm capable of doing that work - and so are you. The very fact you are facing how you feel and trying to find a way to move on and find peace means you are doing a lot of tough, but ultimately very beneficial processing.
Can you try to find some things you're proud of from the last couple of months? How you are still here, still going and still trying to deal with things healthily despite his BS? How you are digging into a lot of strength and courage to get through this?
When you start to switch your thinking around from giving him all the power to recognising your own, things get easier.
And, constant looking on Facebook, as well focusing heavily on how unfair it is and also wanting him to get his comeuppance IS handing him power still. Why? Because unless you actively seek some form of revenge any badness that comes to him will be all to do with him and nothing to do with you. It may come tomorrow or in 5 years time.
Do you really want to give him any more energy and power waiting for it? Does he get even more of your life than he already took?
I think it's ok to be angry and it's ok to want revenge. I've had some moments where I've wanted to text or mail my ex with some good things I've achieved if only to say 'fuck you, you didn't break me' (He rather self-indulgently cried because he 'ruined my life' - when that was very far from the case, while also betraying me.)
But I realise that doing that would taint my achievements because again it would be handing power to him - power to react or not react, to be hurt by my actions or not.
I realised that I want to be ME, not a version of me that is so caught up in my exes energy that I have lost myself.
Maybe that mindset can work for you, too?
Also there is a website called 'baggage reclaim' which is really great, as well as 'chumplady' - Both are funny and wise and have some great advice.
Finally...something which really struck me is this focus on finding someone else. It would be a far better 'revenge' to be so fucking happy and sorted in yourself that when the special new person comes along (and they will) they are just a beautiful extra to your life.