Here's what I know. My ex-wife has nothing to do with my happiness or success. My positive approach to life is how I show up for my kids. They are watching us. They are learning from our actions. How we deal with hard times will inform and set their own internal compass for later in life as they run into challenges.
The trick is breaking the cycle. My little death pony had me on his back and was telling me all kinds of lies about my failures, my upcoming failures, and my ultimate demise as a failure.
When one parent checks out their options for divorce, they are beginning the process of separation and exit from the relationship. And hey, if they like the divorce brochure the attorney lays before them, they might even start leaning into divorce.
Bless your co-parent just as they are. Let go of your expectations about co-parenting. Then parent as best you can. Release everyone, even yourself, from the expectations and dreams you had of a wonderful co-parenting relationship.