Agreed DedicatedDad. Shane you need to move quick. Once those papers are served on either side, it is harder than hell to change it. There are attorneys out there that can work with you on making payments. It is a needle in a haystack, but just keep pushing. Since the kids are older, their opinion of who they want to live with may be a issue. In my state, depending on the age of the child, the judge can give heavy weight to the wants of the 14 yo. This will be a trying time on you and the kids.
DedicatedDad is absolutely right, you have no say or control what happens from this point with what the soon-to-be ex chooses to do or who the children are associated while with her. It is much easier to let go on that now...rather than later. Of course, if abuse is ever suspected, thats a whole different issue.