Contact your lender, when they answer, request to speak with the loss mitigation department. Explain your situation, as stated above, and inform them you would (she your wife) would like to be reviewed for participation in the governments HARP program. The HARP program is/was established for situations much like yours, where you have good credit and not missed any payments. The program will refinance your mortgage, lowering your interest rate, which will lower the payment, and hopefully your wife can afford these payments based upon her income alone. When you are requesting participation in the program, possibly request a mortgage on a 40 year term, further lowering the payments, you (she) can refinance into a shorter term in the future when her income improves.
If the HARP program does not work for one reason or another, request from your lenders loss mitigation department, participation in the HAMP program. The HAMP program will modify the mortgage payment to 31 - 38% of her income and lower the interest rate to as low as 2%. You do not need to have missed any payments in order to participate. You only need to show a hardship, divorce would qualify. Be persistent, call your lender regularly and if one person tells you "no" call back and speak with a manager of loss mitigation.