Can my wife file for bankruptcy without using my income for the means test if we live in different households?

If you live in separate households, you use only your income.

Your wife would not be required to include your income with hers for the means test if either you are legally separated or the two of you are living apart for a purpose other than evading the requirements of the means test. The fact that you moved for work and she stayed to be close to family should be considered a reason for living apart other that for the purpose of evading the requirements of the means test. On the Statement of Current Monthly Income and Means-Test Calculation form, your spouse should check box 2.b., for status as Married, not filing jointly, with declaration of separate households. By checking that box, she is declaring under penalty of perjury that my spouse and I are legally separated under applicable non-bankruptcy law or my spouse and I are living apart other than for the purpose of evading the requirements of 707(b)(2)(A) of the Bankruptcy Code.

This is going to be somewhat a matter of local practice and rulings. Your wife should discuss this in detail with her bankruptcy lawyer.

I had clients who had long been separated & had disparate incomes. His contribution to her household was noted, but their incomes were not combined for means test purposes. However, if your intent is to someday reunite, I think you would get push back from your U.S. Trustee's office.