Pretty myths aren't my area of expertise, but out of curiosity, is there any passage in your bible that explicitly states the word "marriage" must be reserved for the union of a male and female?
Genesis 2:24 ......."That is why a man will leave his father and his mother and he will stick to his wife, and they will become one flesh."
Then there is Jesus quoting these words.
Matthew 19:4-6...."In reply he [Jesus] said: “Have you not read that the one who created them from the beginning made them male and female 5 and said: ‘For this reason a man will leave his father and his mother and will stick to his wife, and the two will be one flesh’? 6 So that they are no longer two, but one flesh. Therefore, what God has yoked together, let no man put apart.”
The last part of that scripture is often quoted in marriage vows. Don't let anyone tell you that marriage isn't God's arrangement. No human has the right to tamper with it IMV.