Welcome to SI and so very sorry you're here. There are some posts pinned to the top of the forum that are great resources. There are some that aren't pinned but have bull's eye icons that are good resources, too. The Healing Library is at the top of the page and has a lot of resources, too.
Are you in IC (individual counseling) just for you to help you deal with your trauma? My second IC was a betrayal trauma specialist and the work we did was very helpful in working through the pain and trauma. Plus, your M (marriage) didn't cheat - your WH (wayward husband) did. Also, have you both had STD/STI testing done? There are some nasty diseases out there that can turn into cancer.
Two books that are generally recommended are How To Help Your Spouse Heal From Your Affair by Linda MacDonald. It's a nice blueprint your WH can follow to help you heal. Unfortunately, healing takes YEARS. It's a marathon and not a sprint. Be gracious and remember that this is going to take time and healing. The second book is Not Just Friends by Dr. Shirley Glass, which may be good for the two of you to read together. I really liked the chapter about windows & walls, which is an analogy to help describe boundaries between the marital relationship and those who aren't in the relationship.
Generally, it's a bad idea to confront the AP (affair partner). You can write a letter and burn it, if that helps. Did you tell the OBS (other betrayed spouse)? This isn't done for revenge or to blow up their family, it's to give the OBS their agency back. The OBS can then have more truth they can have to make informed decisions about their life.
biggest regret and mistake in life
A mistake is forgetting to grab your keys or to forget grabbing a gallon of milk at the grocery store. He made thousands of conscious decisions to cheat on you and then lie to your face.
It's possible that you aren't able to move beyond this, and that's ok. It's possible that you can work through it, and that's ok. It takes a lot of work to R (reconcile). Your WH needs to work on becoming a safe partner and may not be able to do the work to change. Watch his actions to see if they line up with change. It can be that the A is a deal-breaker for you. You'll still need to do the work to heal and process the trauma. It hurts and it sucks.
We're here to help you get out of infidelity, whichever path you take.
BW M 34years, Dday 1: March 2018, Dday 2: August 2019, D final 2/25/21