I haven't quite gotten the answer to this. It would be best if we filed jointly as filing separately will significantly increase the amount of tax owed for both of us but my ex is petty and will likely not cooperate in getting my tax documents.

So if I'm forced to file separately, am I able to claim payments for childcare that she made while we were married? I'm also aware that the first person to file and claim a dependent, will prevent the second person from doing the same. I'm considering just filing and overpaying, then amending my tax return rather than wait on my ex to screw me.