When the wife of a busy young lawyer threatens the lives of their children he is forced to assume sole custody and raise them in the shadow of interference from his former friends.

Still not getting an idea of the whole story here...a logline should summarize the first half of a script, everything up to the midpoint. This sounds like five minutes out of the entire plot, and it isn't clear why these things are happening.

After the psychotic wife of a busy young lawyer tells them she will crash her car with their kids inside he is forced to seek sole custody of the children she has incited against him.

You should give us a more specific inciting incident. 'Threatens' could mean a lot of things. What specifically did she do?

Did she lock the car doors and drive the children into a lake?

Did she fall asleep while smoking and set fire to the house?

Did she force them to watch "The Last Jedi" over and over?

If you are going to use 'threatens the lives of their children' as the inciting incident, then give us the specific event in which she threatened (Endangered) the children's lives.