It hasn’t happened in a long time but I would recommend the following for a quicker cure:
First, wallow in your sadness and cry until you have no tears left.
Then, when you are sick of crying, get mad and do what Bernadette did in “Waiting To Exhale” (giphy above).
What I mean is just fantasize about burning all their stuff.
Instead, donate everything they ever gave you to charity or sell it.
Toss all pictures of them into the garbage (in these modern times, I guess you would delete them from your social media and phone).
Lastly, write a laundry list of every annoying thing you ever disliked about them so that when your mind wanders to supposedly better times, you can refresh your memory about why you are better off without them.
What’s your recipe for recuperating from extreme heartbreak?