``It being the public policy of this commonwealth to protect the unique relationship of marriage, only the union of one man and one woman shall be valid or recognized as a marriage in the commonwealth. Two persons of the same sex shall have the right to form a civil union if they otherwise meet the requirements set forth by law for marriage. Civil unions for same sex persons are established by this Article and shall provide entirely the same benefits, protections, rights, privileges and obligations that are afforded to persons married under the law of the commonwealth. All laws applicable to marriage shall also apply to civil unions.
``This Article is self-executing, but the general court may enact laws not inconsistent with anything herein contained to carry out the purpose of this Article.''