If you can point to a verse in the bible that refers to Mary as perpetually a virgin, I will accept it. Unfortunately you can not because it doesn’t exist. for some reason, around the 4th century, Church leaders started to rebel against the mother of Jesus having sex with her husband.
It could be because God himself forbid adultery. It could be that Joseph was a Jew. There is no sin in sex with your husband.
So, Mary became “Queen of Heaven” and a perpetual virgin 400 years after the crucifixion. She was exempted from original sin in 1854, and she was granted assumption into heaven in 1950. Where is this in the Bible?
Why are you so sure that the Mormons can’t be right, when your religion has changed so much without Biblical evidence?
Here is Biblical proof that Mary and Joseph had other children younger than Our Lord. [Psalm 69:8-9] I am become a stranger unto my brethren, and an alien unto my mother's children. "For the zeal of thine house hath eaten me up"; and the reproaches of them that reproached thee are fallen upon me.
His disciples recalled this scripture here: [John 2:15-17] And when he had made a scourge of small cords, he drove them all out of the temple, and the sheep, and the oxen; and poured out the changers' money, and overthrew the tables; And said unto them that sold doves, Take these things hence; make not my Father's house an house of merchandise. And his disciples remembered that it was written, The zeal of thine house hath eaten me up.
I am not herein arguing that the Mormons can't be right. I am making descriptive rather than prescriptive arguments. My point in this case is not what is true, but rather what is Christian. A Christian is one who accepts the Nicene Creed. By this argument, the LDS might be true, but it would not be Christian.