“If another believer sins, rebuke that person; then IF there is repentance, forgive.”

-Luke 17:3, NLT (Emphasis added)

Forgiveness–according to Jesus–is conditioned on repentance of the offender.

A faithful spouse seeking to see repentance BEFORE forgiving is not being bitter but rather being biblical. They are obeying Jesus’ own words here in Luke 17:3 as opposed to following worldly wisdom on such matters.

DM, what if my cheater NEVER repents?

I think “forgiveness” looks like giving the injustices over to God in these situations. It is obeying another verse:

Dearly beloved, avenge not yourselves, but rather give place unto wrath: for it is written, Vengeance is mine; I will repay, saith the Lord.

-Romans 12:19, KJV

Sometimes that is the furthest we can take “forgiveness” with cheaters who will not repent. We have to entrust them to our good, just God who will deal with them so that we no longer have to carry that burden and can get on with our lives.

Yet, in a sense, they remain unforgiven for as long as they refuse to repent.