It is hard to explain to a loving person who can only give, what the refusal to receive does to would-be givers. If our gifts come out of the substance of who we are, to refuse our gifts is a rejection of our very self. At the same time, the turning away of a gift destroys the reciprocity of love. In place of mutuality, it sets up a hierarchy of love that makes the one who always receives and whose gifts are refused feel empty, powerless, and incompetent to love well, and so unable in turn to receive from the beloved with a grateful heart.
Forgiveness means accepting the core of every human being as the same as yourself and giving them the gift of not judging them. You can be clear about whether or not a person's behavior is acceptable without judging the person. Forgiveness starts with ourselves and extends to others. Accepting that the core of your own being is as precious and wonderful as that of any other person is the greatest gift you can ever give yourself.