If you share children with a spouse you're divorcing, you will likely have that person at least peripherally in your life for the foreseeable future. When the kids are minors, there will be custody exchanges and probably the payment or receipt of child support.
But even when your children are grown and have families of their own, you will still run into your ex at extended family functions, especially once there are grandchildren. All of this makes it worthwhile for the two of you to attempt to heal old wounds and form at least a civil relationship with one another.
Of course, most exes take a little while to achieve good working relationships. The path from divorce court to friendship can be rocky and take years to evolve, but the results are worth the effort expended by the parties.
Putting your kids and their needs first can set the stage for détente between you and your ex. Remember that even adult children don't like to see their parents squabbling with one another during every interaction. Resolving to take the high road is often the better option.
Learning the art of compromise can set the stage for a better post-divorce relationship with your ex. "My way or the highway" is rarely a healthy attitude to have with others — even exes.
It's also important that neither of you attempts to re-litigate the divorce. Instead, remain respectful of one another when your paths cross. Should a custody dispute arise where there is no clear path to resolution, it may be time to seek the counsel of the Orange County family law attorney who handled your divorce.