Welcome to SI and so sorry that you're hurting. If you haven't read the posts already, there are some really good ones posted to the top of the forum. There are some other great posts that aren't pinned, and you can find them by scrolling & looking for the bull's eye icon. The Healing Library is at the top of the page and has a lot of great resources.
If you can, IC (individual counseling) with a betrayal trauma specialist may be helpful for you. Bonus points if they also list infidelity as one of their treatment specialties.
I can't focus, I'm hurt, feel betrayed, but also I feel nothing at the same time
This is the effects of betrayal trauma on your brain. My concentration was shot and I had a hard time focusing for longer than 15 minutes. Your emotions can be all over the place and change without notice. We will make reference to the emotional roller coaster and it can pick you up at any time.
If you need to ask your doctor for meds, please do so. You may not need them forever, but they can help in the short-term. Plus, you should get tested for STDs, too. There are some nasty things out there that can turn into cancer.
Your WH (wayward husband) should read How to Help Your Spouse Heal From Your Affair by Linda MacDonald. It's a fairly short book and is a nice blueprint to help him get started. Another good book is Not Just Friends by Dr. Shirley Glass. (Feel free to read them, too.)
He needs IC to work on becoming a safe partner. It's his job to figure out why he has been doing this. It wasn't a mistake and he didn't goof up. He has made deliberate, conscious decisions to cheat and then lie.
Your M (marriage) didn't cheat - your WH did. Generally, we recommend IC for each. When you get where you feel that you're healed enough, then you might want to try MC (marriage counseling). Many MCs aren't equipped to deal with infidelity. They're there to help with the relationship.
Sorry that you're joining us.
BW M 34years, Dday 1: March 2018, Dday 2: August 2019, D final 2/25/21