See the Form 8379 below. Possible reasons might be that:
- You are in a community property state
- You are the Injured Spouse, not your wife
- You must mark that you are not legally obligated to pay the past due amount
- If you are the only one working, all income (Line 13) is allocated to you, not the other spouse
- Indicate joint return
- Yes, the IRS will use the joint overpayment
