Forgiveness is a beautiful thing. Even though there are still scars, it washes everything clean so forgiver and forgiven can try to heal them.
Forgiveness helps both of them. It helps the victim, the forgiver, open back up to relationship and trust. It helps the aggressor, the forgiven, acknowledge their wrongdoing and try to right it. It helps them recognize how they may have hurt someone else. It also helps them recognize their own scars.