Many people have problems forgiving because they feel like it means they’re required to be a doormat and continually be taken advantage of. That’s flawed thinking, and doesn’t line up with God’s pattern of forgiveness.
Forgiveness is neither turning a blind eye to what happened nor acting like you weren’t negatively affected. Instead, forgiveness addresses the problem, expresses expectations for changed behavior in the future, and refuses to retaliate for the harm done.
Forgiveness is the doorway to your freedom, and your spouse ultimately repenting due to the goodness of God being shown through you (Romans 2:4).