Remember that jealousy is a weapon and that the role of that weapon is to protect your relationship.
When this relationship collapses, there is nothing left to protect.
He is gone, right?
So, refocus your energy on what matters: YOU!
Replace negative jealousy patterns with more empowering mind sets:
"He is free"
"I don't own him"
"He is having a good time, so what?"
"I am free"
These are positive mind sets that tame your jealousy weapon and give it new direction.
Yes! It is like wrestling with thoughts and emotions you don't want but that's what gives you a new edge + the control seat in your mind.
Stay focused! Persevere!
You are on the right track!