Try to forgive for the sake of love. If it doesn't help try to forgive for the sake of logic and rationality. Sadly if that doesn't as well come to your rescue, you may forgive for humanity's sake. But if all these don't work then possibly that person or situation doesn't deserve your forgiveness but let go of that completely. Stay kind to yourself and society.
As the Gardener's treasured Flower wilts and perishes away it's not the Gardner at remorse only. The Flora too no longer receives the love of the most benevolent green thumb!
Self_Respect. As amazing as it can be. It helps us garner sometimes self-love too. In the process we mustn't be misleaded by the veil of self-justification which may portray 'concern and love' as despise.
Not because of the ebb and flow of nostalgia that torment your thoughts to keep holding back. But because of your reluctance. You tried. You gave your best fight. Put your best stake. Had your worst thrashing. You fell. You stood up. You want now to be reluctant and keep building up the dearth of goodness. Don't. You'll heal. It's never the easy deal. It will be tough and painful. But you'll do it. Let Go for not a bleak morn. Let Go for stronger "tommorow you"!