According to Ukrainian law : Ukraine does not recognize dual citizenship. you are either Ukrainian, either not.

A naturalized Ukrainian (mean you in future) must renounce otheir citizenships within 2 years. And voluntary gain of citizenship of other state is reason to cancel person`s  Ukrainian citizenship (means your wife).  In some cases will be automatically cancelled Ukrainian citizenship, in some case after some procedures. 

Its in theory, but in practice people has two citizenship. Do not mix with dual citizenship. Dual its recognised officially between goverments. Two citizenship means. in Ukraine- you are only Ukrainian. Iа you have 2 citizenship ( not dual) you must enter and leave Ukraine only with Ukrainian passport.

in 2014  there was a move to criminilize two/dual citizenship, but it did not become a law.