@kristinw98
You have touched an issue with e-filing that maybe the IRS has not addressed. The IRS will assume that both spouses consented when one spouse e-files a joint return. There is no way to prove or disprove that you agreed or disagreed or didn't even know. Those are arguments you can make to the divorce court and to the IRS when you file for innocent spouse relief. The ex-spouse or The IRS might make an argument that you did know or should have known. That you must have known a tax return was required, that you knew or should have know to ask to see the return, that you knew or should have known to ask about any refund, and so on.
But the real concern is that you take all the steps now to preserve your rights in the future.
