My ex husband lives in Kansas, yet works in Texas where he spends the majority of his time. I live in Arkansas with our 3 children. Since our order was established his income has gone up tremondously while mine has stayed roughly the same give or take a few hundred dollars. However he also has another child on the way and my children are getting older so their more expensive where do I file the paperwork to have then redo our order, Kansas, Arkansas, or Texas.

Where was the original order filed? Do either of you live where it was originally filed?

Generally, as long as one party remains in the jurisdiction that originally issued the order, that area retains jurisdiction. If both parties have moved, then jurisdiction rests where the child resides.