More damage has been done to others by persons leading lives of quiet desperation (that is, doing what they felt they "had" to do) than ever was done by persons freely doing what they wanted to do. When you give a person freedom, you remove danger, you don't increase it.
Yes, letting someone "off the hook" on a promise or commitment made to you may look like it will hurt you in the short run, but it will never danger you in the long run, because when you give the other person their freedom, you give yourself freedom as well.
And so now you are free of the agonies and the sorrows, the attacks on your dignity and self-worth that inevitably follow when you force another person to keep a promise to you that he or she does not want to keep.
The longer damage will far outweigh the shorter - as nearly everyone who has tried to hold another person to their word has discovered.