My boyfriend shares physical and legal custody of his children with his ex wife. She has however been in prison for the last year and a half.

Once the children were in Arizona for 6 months, Arizona took over jurisdiction (power) to enter custody and visitation orders.  Your boyfriend will need to "domesticate" the Colorado orders.  He will need to obtain a certified copy of the last orders from Colorado (this can be done by calling the court there) and file them in Arizona.  Once he files the orders, he can then file a Petition to Modify custody (decision making) and parenting time (visitation) in Arizona and reference those Colorado orders. There has been a clear change of circumstances given the mother's incarceration and her status as a sex offender.  He has reasons to file for a modification here in Arizona, but must take the steps as outlined above before the Arizona court will take any action. *This answer is for information purposes only and does not create and attorney-client relationship between the question presenter and Laura B. Monte, Esq. or Donaldson Stewart, P.C.* *Laura B. Monte, Esq. is licensed to practice only in the State of Arizona.  Any answers provided are based solely on Arizona law and court case law.*