OK so my ex wife has custody of our 17yo son, he is in his final year of High School. She is going to be moving in with her BF out of state, and my son will be living with his sister so he can finish out his last year in the school he wants to be in. I am currently paying child support through a divorce agreement, and is paid as a direct deposit to my wifes bank account, it doesn't go through the court. Now i'm obviously not going to pay her when she leaves, and was going to start paying my daughters rent until he is 18. For conversation sake let's say I am currently paying my ex 1000 a month. If she decides to leave him with his sister, would she then have to start paying some money for his care as well? to a point where I could lower my portion?