Should we file 2014 tax return jointly?

That 7.5 percent is for those 65 years and older and only until December 31, 2016.
http://www.irs.gov/Individuals/2013-Changes-to-Itemized-Deduction-for-Medical-Expenses.

Consider the possibility of filing separately from your spouse. The tax code lets you deduct only the qualified medical expenses that exceed 7.5 percent of your adjusted gross income. On a joint return, that might not amount to much, but it could be significant on an individual return. Likely candidates for "married filing separately" are spouses without health insurance or those who entered a nursing home. Nursing home, home-care costs, and private nursing are generally deductible as a medical expense.