Love your kids with everything you've got. Let go of your ex, as best you can, and focus on the impact your love is having on your kids. Stay true to that value and you will always choose the high road.
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.
Down has become the new up, and I have become a new single dad, still committed to his kids, and in many ways, to his ex-wife as well. We are still a family, still connected, even when we're not together.