I’m going to say something that might be controversial and not the answer you are looking for.
There is no such thing as “closure”.
This is a made up concept that suggests that after experiencing something difficult or painful, you can put those feelings away forever. That’s a fantasy. It’s not unlike the idea that grief comes to a complete end, and life resumes as it was before. It doesn’t.
It’s true that we can repress our feelings for extended periods of time, but there are always consequences to this.
You can’t make your feelings go away, but you can learn to manage them better. A big part of managing our feelings is often related to how we understand them.
For example, a person with little self-worth, may feel that nobody will ever love them again, after their partner leaves them. They felt that their life has no meaning without the person in their life.
By understanding that they are devaluing themselves based on falsehoods expressed to them by their caregivers, due to those caregivers own lack of self-worth, they start to understand that this is not a truth about them, but an unfortunate series of events, and lousy luck being born into a particularly dysfunctional and toxic family environment.
Through a healthy therapeutic relationship they may begin to see themselves in a new light, and recognize aspects of themselves that they truly value.
Therapy does not help with closure, since it doesn’t really exist, but it can help yon become the best version of you, in which you see your losses in a very different light, and may realize that you are stronger than you ever imagined.