Matthew 19:4-6.
The historical portrayal of events as they happened is not equivalent to condoning or advocating them.
Matthew 19:4-6
New King James Version (NKJV)
4 And He answered and said to them, “Have you not read that He who made[a] them at the beginning ‘made them male and female,’ 5 and said, ‘For this reason a man shall leave his father and mother and be joined to his wife, and the two shall become one flesh’?[c] 6 So then, they are no longer two but one flesh. Therefore what God has joined together, let not man separate.”
So, does that mean that marriage can only be one man and one woman? I don't see that "exclusivity" there.