Disclosure of Return

An married person who is unwilling to sigh a MFJ return (for any or no reason) is required to file a MFS return. Unless the divorce agreement (or final divorce stipulation) or some other agreement requires that the former spouses share tax return information, I don't see how one spouse (former or otherwise) can force the other to share it. Also, W doesn't need to see H's return in order to properly prepare and file hers.

As a practical matter, the two former spouses may find it mutually advantageous to share a minimal amount of information. They are both required to use the same Standard Deduction or Itemized Deduction choice and if one chooses Itemized Deduction the other is also forced to use Itemized Deductions even if it is less than the Standard Deduction. If they don't communicate and both chose the same Deduction method, there will be no problems. If they don't communicate and choose different Deduction methods, the one who chooses the Standard Deduction will eventually have an unpleasant surprise.

If you are asking is there a statute that bestows some right to a spouse for disclosure of the tax return, the answer is no. If you are asking whether divorce court judge can issue a valid order to a spouse to provide a copy of a separate federal return to the other spouse, I believe the answer is also no. However, it isn't necessary to issue such an order. State court divorce judges have other tools at their disposal. They can order the parties to cooperate and share information in order for each party to file an accurate return. If the parties reside in a community party state, they can order how community income should be split. They can also divide up refunds and determine how tax liabilities get split. In all of these cases, one party can easily find themselves in contempt for failing to comply.