#1 - you pretty much have to file jointly if you're married and living together.
#2 - Do you have a retirement plan at work? I'm guessing yes because the guidance from the IRS is pretty clear on whether or not you can deduct a TIRA if you also don't have retirement at work.
#3 - If the answer to #2 is yes, then is your MAGI for 2017 under $186K ($196K for partial)? If yes, then she can deduct her tIRA contribution. If no, then she can't and Backdoor Roth IRA is the play.
Without specific numbers, it reads like your MAGI will be between $186K and $196K. Or is that your combined gross? Because around here, your MAGI can be quite a bit less than your gross. 401K, health insurance, HSA / FSA, and some other things you might be doing through payroll would all lower your MAGI.