Welcome, Horselady. I'm glad that you found us for support, but not that you had the reason to come find us. As was mentioned above, look in the upper left corner in the yellow box, and click on The Healing Library and start reading. A bunch of posts with red "targets"" next to them have been bumped up to the first page as well. Please read them too. All really good information by people who have BTDT. And right now, information and knowledge of "typical" cheater behaviors are going to be of help to you.
Listen. You didn't make the decision to cheat. Your WH did and your X did. YOU didn't force them to commit infidelity. It was their decision, their choice. They have to own that. You don't have the power to have physically forced them to do that. And whatever waa waa excuses that they make about being so unhappy, so tempted, so whatever, are exactly that excuses. You both were in the same marriage and only one of you felt the need and the utter disrespect and disregard to justify going outside of the marriage. And it wasn't you.
Make sure that you're staying hydrated, you're eating what you can, and get as much rest as possible. If you can't keep anything down, sip a whole-food nourishment drink (Ensure is one brand, there are several). You don't have to decide anything now. Use this weekend to try to read through here, detach as much as possible, and do some thinking about what you want, need, and deserve. And come back often for support. It can be slow on the weekends, but we're all here for you.
From one horselady to another, (((hugs))) (that means that I'm sending you multiple hugs).