What does "closure" mean when people talk about situations and relationships?

Sehen Sie eine Übersetzung

I don't fully trust online dictionaries and google with the Russian language, but I'll still paste a definition below anyway.

"the feeling that a sad or unpleasant experience has now finished so that you can think about and do other things
чувство, что грустный или неприятный эпизод в жизни завершился, и появилась способность думать о чем-то другом"
https://dictionary.cambridge.org/us/dictionary/...

A woman breaks up with a man, and the man doesn't know why she ended the relationship, he thought everything was perfect. He has a difficult time forgetting about her and the relationship. Finding out the reason why she broke up with him would give him some closure, give him some peace, so that he may be able to stop thinking about the situation, and move on with his life. So it's kind of like, information that allows you to stop thinking about something, so that you could close that chapter of your life, like it were a book. Information that allows you to "end" or "close" part of your life.

In other situations, it can kind of be like.. There is a mystery, what happened to someone or something? Closure is getting the information that you need to consider a situation resolved in your mind, so that you can stop thinking about it

I can be terrible at explaining things, and I feel like I repeated myself in some ways, but I wanted to try and explain.