Most likely even if you were to make believe that nothing happened, this will start to cause a lot of stress and tension on you and your relationship because you still know about it. This is a pretty big betrayal of your trust, so even if everything appears fine on the outside, this is a problem that will continue to undermine the foundation of your marriage until it is addressed. It may not be easy to confront him, but it probably is necessary in order to provoke the changes that will keep you marriage strong and lasting.
Knowing that he is committed to your marriage, that does significantly increase the odds that you will both be able to make it through this. I would highly recommend marriage counseling which will help you both to repair the damage that this has caused, as well as address any problems that may have led to this point. Even if you don't go to counseling, just being on the same page and working on this problem together can be a great start.
You certainly don't have to confront him today. It may be easier for you to do that if you've had a few days to consider what you want to say, and what the best way would be to have this conversation with him. I definitely wish you the best with this, and if there's anything else I can do to help please let me know.