Hi, My spouse's MAGI was under threshold before marriage to make Roth IRA contribution. However, when filed married jointly, MAGI is over limit. What should my spouse do?

Filing a joint tax return, then your spouse will need to take corrective action with regard to the Roth IRA contribution.  

The following TurboTax help article will give you more information about the options available in this situation:

What if I made an excess Roth IRA contribution because my income is too high?