My ex knew I would not sue her for 50/50 custody. She didn't want to lose 50% of the time with her kids. 30% sounded almost palatable. Painful, but well worth the freedom she imagined just ahead, as she headed towards becoming a single mom.
I had the joy and passion in spades. I had a misaligned marriage which generated two wonderful kids. Today I have reset myself towards a creatively fulfilling life.
You can't replace or redo the lost time. But you can grow back into your full self, into a whole parent, and be even better when they are with you.