“Even now,” declares the Lord, “return to me with all your heart,
    with fasting and weeping and mourning.”

Rend your heart and not your garments.

-Joel 2:12-13a, NIV

What is described here in Joel is repentance.

The prophet talks about genuine remorse or grief over wrong doing and not simply outward displays–like tearing “rending” one’s clothes. That is not enough.

Along with this, the prophet does not guarantee God will relent from punishing the people. It is left as a “maybe” after true repentance (see Joel 2:14).

These give clues to what might happen in some situations with a cheater.

True repentance has to be evident. It cannot just be image management behavior. The grief over the wrong and harm done must touch the cheater’s heart genuinely for real repentance to be present.

Also, like this Scripture, the repentant cheater does not try to control the outcome. They do this without the expectation that the offended party “must” do anything (like stay married to them).

In these sort of circumstances, I see hope for a cheater.

Even if the marriage still ends, the cheater still gains from learning from the experience and transforming into the person God expects him or her to be. “Doing right is its own reward” sort of thing.

When cheaters own their destructive behavior fully and do not minimize or excuse it, I have hope for them. There is something to work with there. 

When they do not try to control or manipulate what happens to the violated relationship, I have hope there, too. 

Both take humility.

Both are hard.

Both are evidence of a repentant heart.