I believe that living with anger, creates an angry life. Showing the angry life to your kids is not the lesson you'd prefer to give them. Discharge your anger however you need to do it, but quit firing poison darts at your co-parent. You are liable to hit one of your kids instead.
I wish my co-parent all the joy and love in the world. I can no longer provide any of those things. But I can be a soft cushion when she needs to hit or collapse into something. I resolve not to hit back. But, I won't stand-in for the drama anymore. I will only take my responsibility. I will only pay attention to the business between us as we continue together in co-parenting.
I'm a bit closer to my ex-wife now, having seen a glimpse into her life. I know we're both doing the best we can. And Boyhood celebrates that triumph both alone and together.