I'm not being snotty, but explain to me how that works. Because when I did the numbers for the very same situation you listed, just for kicks, we would have been far better off if we were single filing separately. What did I miss?
Ok, let's say you have $10,000 in deductions (that's in between the single standard deduction and the married standard deduction).
Also let's say you make $80,000 gross and your wife makes $0.
Filing singly, your AGI is $80,000 - $10,000 (deductions) - $3,700 (exemption) = $66,300. The single tax on this is $12,706.
Wife's tax is $0, so total is $12,706.
Filing married, your AGI is $80,000 - $11,300 (standard deduction) - $7,400 (2 exemptions) = $61,300. The married tax on this is $8,349 or 35% lower.
This is based on 2011 tax tables, available here:
http://www.irs.gov/p...pdf/i1040tt.pdf The brackets/formulas are at the very end of the document. Since the married tax brackets are much wider, you are taxing the same amount of money at much lower rates. I think the effect becomes much more pronounced at the higher tax brackets, and much less as the two spouses incomes approach parity. I think it goes away and becomes a detriment as total income of the couple goes way up.