Unfortunately, once you've filed a joint return with your spouse, it is not permissible under applicable Federal law to change your filing status from joint to separate.
You past tax filings are a matter of record.
I do not think that changing them in anticipation of your divorce would be of much advantage, if any, in the divorce proceeding. Your wife does not seem to have any reasonable expectancy of spousal support, if she has had none for 3 years. The equitable division of marital property should not be impacted by your tax status either.
Perhaps, you have a specific concern or idea. I recommend that you discuss this with an attorney. Given that your spouse is out of the US, you would benefit by having counsel to insure that the legal action is properly initiated.
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My answer is not legal advice and does not establish a client/attorney relationship. The question may not be a complete or accurate description of the problem and there is no chance to ask a follow up question. It is impossible to give complete advice without a thorough discussion of the facts, such we would have during an initial consultation. Further, laws are different from jurisdiction to jurisdiction and frequently change. So, please, do not act on any information provided without consulting with a lawyer licensed to practice in your jurisdiction who has experience with the kind of issues that concern you.
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