Breakups can be amazing, freeing, traumatic, dramatic, or all of the above. It all depends on how you deal with it.
Wallowing in sadness and maybe regret tend to be the default for a lot of people. What did I do wrong? What could I have done better so that they would have stayed? Why did they make me so angry that I lashed out? So on and so on.
Staying in that circle of what-ifs is just that, a circle. It starts with "what could have been different?" which leads to "how would that have played out?" which leads back to "what could have been different?".
Instead, try a different line of questioning.
What did I learn from it?
How did that person lift me up and support me emotionally?
How did they tear me down?
What was going on in their lives that might have led to a misunderstanding?
What were the unspoken expectations?
How did this change your personality?
How will you move forward now?
Make it a defining moment. The relationship was the old you.
Who is that new you going to be? How are you going to now act?
What did you learn from that old relationship that you will never let happen again?
What was amazing that you want to have happen again?
Collect all of the other persons things and do something with it. Return it? Throw it all out? Donate it to good will? Burn old photos? Something that makes this moment a special transition to the new you.
Let that old you go. Let that old partner go. Go and enjoy the new you.