Welcome to SI, the best club nobody wants to join. There are some pinned posts at the top of the forum that are very helpful. Another treasure trove of information I the Healing Library.
Forgiveness can have many meanings, but you don't have to work on that right now. Nobody said you have to forget.
An A (affair) is not a mistake. A mistake is forgetting to grab a gallon of milk at the store. An A is thousands of conscious decisions to betray.
A good book for your WH (wayward husband) is by Linda MacDonald, "How to Help Your Spouse Heal from Your Affair." It's fairly short and helps create a roadmap of what he can do to help you.
Another book recommendation is "Not Just Friends" by Dr Shirley Glass.
Right now, watch his actions and don't listen to the words. His actions will show you if he's doing the work to be a safe partner.
IC (individual counseling) for each of you. If you can see a betrayal trauma specialist, especially one with infidelity, it will be helpful.
We're here to help get you out of infidelity, whether it's D (divorce) or R (reconciliation).
There's a saying here to take what you need and leave the rest.
Keep posting and practice lots of self-care.
BW M 34years, Dday 1: March 2018, Dday 2: August 2019, D final 2/25/21