Full or partial waiver of legal capacity by a citizen and other deals aimed at incapacitation are considered void according to Art. 22 part 3 of the Civil Code of the Russian Federation.

Your agreement is void according to Art. 168 of the Civil Code of the Russian Federation as non-conforming the laws , in particular the Constitution of the Russian Federation and the Law of the Russian Federation № 5242-1 "Right of Russian citizens to freedom of movement and choice of residence in the territory of the Russian Federation" and the Family Code of the Russian Federation.

Therefore you do not have any legal basis to require termination of the sale/purchase contract and enforcement of other provisions of your void agreement. You can conclude a marriage according to Art. 12 of the Family Code of the Russian Federation, mutual agreement of a man and a woman to conclude a marriage and achievement of marriage age are the only requirements for conclusion of a marriage. A marriage can not be concluded in case any of the circumstances mentioned in Art. 14 of the Family Code of the Russian Federation exist, i.e. a marriage can not be concluded by persons in case one of them is married; such persons are immediate relatives, an adopter and an adoptee; in case one of them is declared legally incapable due to a mental disease. This list is complete.