If he is truly committed to restoring the R, you'll get more than one chance. Tell him you need him to step up as a friend and a father to your children before he can be anything else again.
I'm not so sure about the CS office thing if he is paying voluntarily at guideline or more. They are meant to be involved when you need help with enforcement, and most men hate them.
M 16 yrs, WH62, P54 3 adult blended kids EA 11/13, BD1 6/14 PA fall 14, BD2 2/15 Piecing 2015, BD3 12/15 Separated 4/16 WH moved OW in 5/16 Divorced 6/15/17