If your 'agreement' isn't filed and cert'd by the courts, its not worth the paper its written on in Ohio D-. We're dealing with the very laws you are in case you didn't notice my location. lol In our case, his ex (AND her mother) would have to sign it in front of a judge in order to be legal, but I won't go in to that.
Just get a good attorney. Ours was ready to take a swipe at my old man the other day but one look in to his eyes warned him off. lol ALWAYS take the offensive in these cases as it usually stands good in front of a judge. If the first hearing doesn't go in your favor (or at least impartial) put in for a different judge.
Odd too, Female judges are more for the men since they know firsthand how many women scr*w over the men. I was standing beside him in court for his divorce and she (judge) asked me whom I was... I told her straight and she said, fine.
And then called for the soon to be ex who didn't bother to come... and said ok, Miss Gemini, take your man home and treat him right. lol