Once you have decided to move on, you must understand that your former partner owes you nothing. Closure is a myth we like to "go for" in our breakups, but closure is up to us as individuals.
Like a broken arm that heals stronger than before it was broken, what if your big love can come back with more resilience, more compassion, more flexibility when things go dark? That's the plan.
Some of my depression is sadness at the massive amounts of my kid's lives I'm missing. That's real and that's going to make me sad. I don't have to dwell on it, but when it comes up I feel it, acknowledge it and thank my heart for feeling so strongly.