I mentioned Mrs. Z. before. This was a woman who never recovered from her husband’s adultery. She lived the rest of her life feeling the hurt and betrayal, never letting go.
You have to let go.
You have to get through the first months after the revelation, striving not to disrupt your life; that is not rush into the night, not create a war, not make his adultery the centrepiece of your existence.
It is all about you. Whatever you have to do to regain balance, to be who you were, do it.
If you need to have your own affair, if you need to ‘live’ at work, whatever it is, give it to yourself, so that you can gain the balance to make your next decision.