Ok. New data.
- You want to continue to be there for the kids and support then in appropriate ways
- Your son needs extra care beyond post-divorce care
- You mention your OSO has a "fatal attraction" that is unhealthy.
- You want to stop living in unhealthy ways.
So could go with
- create your wellness plan to remove yourself from toxic environment and relationships so you can become more healthy over time in all your healths (Learn to put you first. If you die from "unhealthy way of living that will kill me", you can't be around help you kids.)
- create a kid care plan to provide for the children and their needs in appropriate ways
- ending your participation in the marriage to be free of bitchy wife
- ending your participation in the polyship to be free of fatal attraction OSO
Maybe it is enough work for today to decide those goals as your mission? So you can go to sleep tonight feeling one microstep closer to resolution?
Then start to work with the counselor and your lawyer/mediator to start coloring in the picture better tomorrow?
You don't have to solve it all in one day. It is going to be a process. But you are moving towards being free of marriage and polyship hooha so you can be a healthier, stronger person. Which benefits both you and your kids. That's a good thing.
It doesn't sound like an unsolveable
problem. It is a big problem that requires you to come to a decision about what your current mission is. Sounds like you have that.
Next it is about identifying and organizing the rest of the actions to support each of those mini goals. Make the "to do list" for each. Your counselor can help you with your thought process and help you figure out what other help you may need along the way. Your lawyer/mediator can help you with your legal process.
Once planning stage is done? You work to achieve the steps to support and knock out the mini goals.
Once all the goals are knocked out, you have completed the mission.
You can do this. One thing at a time.
Hang in there.