First, we all have the exact same marrage rights, as long as it is to an agreeable party of the opposite sex.
Tghis has been codified for 5000+ years.
Hammurabi's code:
Marriage retained the form of purchase, but was essentially a contract to be man and wife together. The marriage of young people was usually arranged between the relatives, the bride- groom's father providing the bride-price, which with other presents the suitor ceremonially presented to the bride's father. This bride-price was usually handed over by her father to the bride on her marriage, and so came back into the bridegroom's possession, along with her dowry, which was her portion as a daughter. The bride-price varied much, according to the position of the parties, but was in excess of that paid for a slave. The Code enacted that if the father does not, after accepting a man's presents, give him his daughter, he, must return the presents doubled. Even if his decision was brought about by libel on the part of the suitor's friend this was done, and the Code enacted that the faithless friend should not marry the girl. If a suitor changed his mind, he forfeited the presents. The dowry might include real estate, but generally consisted of personal effects and household furniture. It remained the wife's for life, descending to her children, if any; otherwise returning to her family, when the husband could deduct the bride-price if it had not been given to her, or return it, if it had. The marriage ceremony included joining of hands and the utterance of some formula of acceptance on the part of the bridegroom, as "I am the son of nobles, silver and gold shall fill thy lap, thou shalt be my wife, I will be thy husband. Like the fruit of a garden I will give thee offspring." It must be performed by a freeman.
http://www.fordham.edu/halsall/ancient/hamcode.htmlIF you want to join one of the same sex, well, don't let me stop you, just don't pretend it is a marrage, 'cause it's not.