Child Support - Ex self employed and not paying based on what he truely earns?

[Lise D]

When we first separated, my ex and I agreed on a weekly CS payment that would take care of the daycare costs (this was 2 years ago, when my daughter was only 2). He also was giving extra money as needed for clothes and assisting with activites (she takes dance & soccer).

He is now with another woman and they are having a baby. He no longer provides for the extra costs and now that she is in school, my costs have gone up (cost for school, school supplies, activities, parties, etc...). He no longer assists with activities and its been ages since he's helped with clothes. He doesn't contribute to the health care which I provide (for all of us). How can I take him back to court for the extras he's no longer paying and prove that there are jobs under the table.

My boyfriend suggested that by requesting documentation of his living expenses, I could show that he could not afford his lifestyle on the income he claims. Is this valid?

If it helps, I live in RI and the CS order is just over 2 years old.