That's exactly what forgiveness is, letting go of the resentment and anger plus take the control from the person hurting you and regaining your control over the person/situation. The saying we always hear, "I forgive you, but I won't forget.", but it certainly doesn't mean making up with that person.
William has to feel alone at times and I hope he has not only support from the rest of the family, which I think he does, but from the outside also, but it can be lonely when his father continues to bend over backward towards the prodigal son and wife with the AOC pressing his case for the "wayward son and wife". Justin Welby should stay out of fray, if I was William, I would flat out state that I wouldn't want Welby due to his bias for Harry, I'm sure it wouldn't go anywhere. Families can be so maddening and unfair.
I think we all get very angry with Harry and Meghan because none of us have treated our families as horribly as these two have while having no guilt about it. Justin Welby must be very naive and easily manipulated, I don't know.