You don’t always get closure. Sometimes you just close the tab yourself.

Closure is usually imagined as something the other person hands you: the explanation, the apology, the conversation where it all makes sense. Often that never comes, because they have moved on, or they do not know, or they would not tell you. Waiting for it keeps the thing open on your behalf. Deciding you are done is less satisfying and entirely available.

If something has been unfinished for a while, give it one ending of your own. Write what you would have said and do not send it, then stop rereading the messages. The last step is yours to take.