Only just seen your post, hope you're feeling more together this morning.
Know how bad it is, how much it hurts too. Unfortunately theres too many of us in our position.
I'm two years on from me ex leaving this month. Not been easy, we've hit rock bottom too many times, but we've got something my ex gave up and thats trust in each other. My two younger sons stil love their Dad despite what hes done, and his actions in always putting his new partner and her children first, they mostly see through his lies, but hes not part of their daily life any more hes just a 'Sunday father' and thats when hes not got anything better to do.
Takes a lot of getting used that your ex no longer loves you, or cares for you, and someone else is his priority now. Its still very early days for you, just concentrate on getting through each day one at a time, if you can't do that, then break it down into hours to cope with until you are getting by again.
I've lurked on my ex's new partners FB too, does me no good, shes friends with a few relatives i'm friends with, done me no good, and definately doesn't help when she posts comments under ones i've posted! Thats how i found her on there.
Hoping you've got something nice to do to today, and sending a virtual hug, you sound like you need one big time x