And, please, don't aim barbs at your kids meant to hurt your former partner. It never works as expected. Arrows fired at your ex will always affect your children on the way to the target.
You can't have kids by yourself. Your partner is just as important. Why would it be different when you no longer live together?
I may not reach serenity with my ex-wife and her new husband ever. That's okay. The serenity is within me. I am doing, have done, and will do the best I can to support my kids and keep my relationship to them above the fray my ex continues to keep seething around us.