Don't let you custodial mom walk all over you. Just because she's got the state's attorney's behind her, doesn't mean she can disobey the law. In my ex-wife's case, she simply didn't show up to some of our Attorney General's appointments.
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.
When we started down the road of negotiating a cooperative divorce (because it's all about the children) our divorce and parenting plan counselor also suggested 70-30.