Marriage with a citizen of Ukraine may have the following advanteges:
Serves as grounds for obtaining a temporary residence permit
A child born in such marriage can also receive Ukrainian citizenship, regardless of where he or she was born - in Ukraine or abroad.
After two years in such marriage, you get an opportunity to get permanent residence permit
You can exchange your valid temporary residence permit for the same one, but issued on the basis of marriage. In this case you don't need to leave Ukraine and go for a visa.
After two years of marriage and receving of permanent residence permit, thyou get an opportunity to obtain Ukrainian citizenship.