When you never truly get closure from something in your past, how do you deal with it and move on?

Why hold on to it? It never profits us and just keeps us living in the dead past. We can't change that, but there is one thing we can do, and that is love ourselves enough to change what we can today, and because we learned from our past, it taught us how to live better by doing better. We can even make our own closure for the past, if we weren't able to, then. Whatever that looks like to you. Nothing is too weird. I've even written my feelings down on a piece of paper, in detail, whatever I wanted to write or yell about or whatever, and then I released them to God by taking them outside and burning them in the trash barrel, letting the ashes and smoke reach up into the heavens. That was my closure. Some may want to write a letter to someone apologizing, and then release it to God. Whatever it takes for your heart to feel better, is what you can do. It's called Life, because we we're meant to live it, not bury ourselves in the past.