Forgiveness is largely an act of love for oneself.
Loving and taking care of oneself is often something codependents struggle with. If you love yourself, you will forgive others, regardless of if they ask for forgiveness. I forgive so that I may gain peace. Also, if you love yourself you will set boundaries and protect yourself. This concept is not at odds with forgiveness.
The following quotes are taken from the Spouse and Family Support Guide, chapter 12:
"Forgiveness includes a process of letting go of burdens that keep us from experiencing the Savior's peace."
"We will find healing as we forgive others."
James E.Faust: "The Lord requires us to forgive all men for our own good because hatred hinders spiritual growth. Only as we rid ourselves of hatred and bitterness can the Lord put comfort into our hearts."
"Forgiveness does not mean that we condone our loved ones' poor choices or allow them to mistreat us."
"As we forgive, we leave behind feelings that...have the power to canker, fester, and ultimately destroy."
"Forgiving someone when we have been wronged or hurt can be very difficult-especially when these offenses are regularly repeated. But this is part of what it means to be a disciple of Christ."
James E. Faust: One reason for postponing forgiveness "is waiting for the wrongdoers to repent before we forgive them. Yet such a delay causes us to forfeit the peace and happiness that could be ours."