There is real pain, soul trauma with the revelation of an affair. The pain is often the most intense pain (at least it was for me) to ever be encountered. Maybe it will be more prudent to play it safe, be buds, keep the majority of the benefits of marriage, but not put my heart out there because I never, ever want that soul explosion ripping up my insides again. That seems to be the safer way.
But safety is an illusion. No matter what there is always risk and we put our hearts at great risk when we choose not to love. C.S. Lewis said it this way,
"To love at all is to be vulnerable. Love anything, and your heart will certainly be wrung and possibly be broken. If you want to make sure of keeping it intact, you must give your heart to no one, not even to an animal. Wrap it carefully round with hobbies and little luxuries; avoid all entanglements; lock it up safe in the casket or coffin of your selfishness. But in that casket — safe, dark, motionless, airless — it will change. It will not be broken; it will become unbreakable, impenetrable, irredeemable.
Now that's a risk. Not loving again puts our hearts in danger of becoming cold iron. Nothing gets in but nothing comes out either. Comparing it to our physical heart, nothing gets pumped back in and nothing shoots back out taking life to our limbs.
Gerald Sittser in a A Grace Disguised pondered loving again during his grief after the death of his wife, daughter and mom. He came to this conclusion,
“The problem of choosing to love again is that the choice to love means living under the constant threat of further loss. But the problem of choosing not to love is that the choice to turn from love means imperiling the life of the soul, for the soul thrives in an environment of love. If people want their souls to grow through loss, whatever the loss is, they must eventually decide to love even more deeply than they did before.”
For God to redeem the pain of betrayal there must be a choice to grieve and eventually a choice to love even more than before. It's the spirit's finest work of alchemy. The Holy Spirit takes the common scrap metal resulting from the affair and through grieving and choosing to love again (which I believe requires tremendous trust in God to ultimately fully face the pain) transforms the heap into sky illuminating gold.