Rather than project your fears at your spouse, why not look into yourself as to why you had the A?
I'm certain one of those why's will be a fear of abandonment and your coping skill was to have a plan B lined up; i.e having the A.
That's just a surface assessment of it but I believe you're robbing yourself and your W if true intimacy due to your fears. You never got married thinking she'd be ending it, similarly, your W didn't take those vows with a view that you'd be betraying her. It's a risk that you should gladly take for the faith she's putting in you, if she has truly forgiven you after your A. I believe it may be too soon to express forgiveness but timeframes vary for everyone.
Rather than focus on what she 'may' do, why not exert energy into what you CAN do for her. If it means digging into your whys and seeing an IC and committing to fix what's broken in you, I believe that will be more productive than having a few thousand talks on what the possibility if her leaving you is...
Just my 2 cents, take what's beneficial and leave the rest.