It also depends on how much he owns his betrayal. Has he admitted all, and accepts full responsibility?
So, if raking up debt : he fully sees where he went wrong and knows how to change.
If cheated once: he knows why he did it, and doesn’t blame it on alcohol.
If an affair : again, he has insight in why it happened, and doesn’t blame it on OW (‘I couldn’t say no’ , yes, I’ve heard that one..🙄)
Without him owning the betrayal, he won’t be able to make the necessary changes, and it’s likely you’ll end up in similar situations.
And I second a pp - a 20 yr marriage might be worth putting the effort in. Not living together and trust already broken at this stage, not so..
But, even with all the insight in the world, only you know deep down if you are able to forgive.
Trust yourself and don’t waste 2 years trying when you actually know you’re not going to be able to find that trust with him.