My soon to be ex and I are in the middle of a divorce/custody battle. We have a temporary order in place for joint custody with me listed as the residential custodian. I also have temporary exclusive occupancy to the marital residence He pays monthly child support to me. Due to his schedule, the children are with him about 20 days per month. In 2011 and 2012 I claimed both kids on my taxes and 100% on real estate taxes on the house. I never asked, I just did it. I did the same this year but he is now saying that I am not entitled to do so and that we should each claim one kid and 50% of the house. He said that if I don't amend my returns he will escalate the issue to the attorneys. Will I have to amend my returns?