Should I pursue unpaid child maintenance despite a good co-parenting relationship?

[Skyeblue91]

I understand I may have had a ton of backlash on my previous post.
Ive decided not to move.
But now I have another dilemma. I need opinions.
My ex husband and I have been divorced since 3/13/18.
In the divorce decree it says that he is to pay $420 a month for both of my boys (13yrs and 16yrs old).
By calculation, he has paid one month of that since our divorce.
So for 85 months, I have not received a thing.
He is in their lives and we have 50/50 custody but they live with me and have lived with me since we divorced.
He is on his 3rd marriage. He has a good job and his wife is an RN.
We get along for the most part and his wife gets along with me well.
But I do struggle financially. Is it worth going after? I feel like this will lose the good coparenting strategy we have.

How does 50/50 work if they live with you?

He is suppose to have them certain periods of time but he never has. I believed we agreed on one week on and one week off but that has never been the case.

So what is your definition of a good co parenting relationship

He does come over a couple of times a week to see them and we are friendly towards one another. He gets them every other weekend. We don’t argue or anything.