Hey there. I'm so sorry that you had to find this place, but I am happy that we can help support you. This is a place that no one should have the reason to come looking for.
First off, if you have not already, take a look in the upper left corner, at the yellow box, and click on The Healing Library. Start reading. There's a lot of good information there from people who have walked this path. Any posts that you see in this form that have a bulls-eye next to them are good posts to read as well. You might have to go back a couple of pages to find them all, but they are filled with good, tactical advice.
Your WH has, at this point, essentially abandoned you. He's being a coward as well as being a liar and betrayer. Your priority right now should be YOU. Eat what you can if you can't keep food down (and it's not uncommon to throw up a lot), get a whole-food nutrition drink like Ensure and sip on that. Stay hydrated. Try to rest. You are going to feel like your head is exploding and your emotions will flip-flop constantly. You are NOT going crazy. This is normal. This is how normal people react when they receive a shock of this kind.
I would like you to consider one thing. Tell the OWs H, if you have not already. He deserves to know what his WW has been doing and with whom.
Keep coming back for support. Vent away here we are all here for you. It can be slow on weekends, but be assured, we all care. (((hugs)))