Not a Lifelong Virgin
Mary’s virginity is a vital truth. The conception of Jesus in Mary’s womb was done by the miraculous work of the Holy Spirit (Luke 1:35-38).
But Scripture does not suggest that she remained a virgin after marriage - on the contrary. That belief is not only contrary to scripture, but gives the impression that marital sex is tainted or even sinful - but our sexuality is a beautiful gift of God, to be expressed in the context of covenant - marriage.
This from gotquestions.org:
‘It is the official position of the Roman Catholic Church that Jesus’ mother Mary remained a virgin for her entire life. Is this concept biblical? Before we look at specific Scriptures, it is important to understand why the Roman Catholic Church believes in the perpetual virginity of Mary. The Roman Catholic Church views Mary as "the Mother of God" and "Queen of Heaven." Catholics believe Mary to have an exalted place in Heaven, with the closest access to Jesus and God the Father. Such a concept is nowhere taught in Scripture. Further, even if Mary did occupy such an exalted position, her having sexual intercourse would not have prevented her from gaining such a position. Sex in marriage is not sinful. Mary would have in no way defiled herself by having sexual relations with Joseph her husband. The entire concept of the perpetual virginity of Mary is based on an unbiblical teaching, Mary as Queen of Heaven, and on an unbiblical understanding of sex.
So, what does the Bible say about the perpetual virginity of Mary? Using the New American Bible, which is a Catholic translation, we can see that the perpetual virginity of Mary is not taught in the Bible. Matthew 1:25 NAB tells us, "He had no relations with her until she bore a son, and he named him Jesus." He, Joseph, did not have sexual relations with her, Mary, UNTIL after she bore a son, Jesus." The meaning of this Scripture is abundantly clear. Joseph and Mary did not have sexual relations until after Jesus was born. Matthew 13:55-56 NAB declares, "Is He not the carpenter’s son? Is not his mother named Mary and his brothers James, Joseph, Simon, and Judas? Are not His sisters all with us?" Catholics claim, correctly, that the Greek terms for "brothers" and "sisters" in these verses could also refer to male and female relatives, not necessarily literal brothers and sisters. However, the intended meaning is clear, they thought Jesus to be Joseph’s son, the son of Mary, and the brother of James, Joseph, Simon, and Judas, and the brother of the unnamed and unnumbered sisters. Father, mother, brother, sister. It is straining the meaning of the text to interpret “brothers” and “sisters” as "cousins" or "relatives" with the mentioning of Jesus’ mother and father.
Matthew 12:46 NAB tells us, "While He was still speaking to the crowds, His mother and His brothers appeared outside, wishing to speak with Him." See also Mark 3:31-34; Luke 8:19-21; John 2:12; and Acts 1:14. All mention Jesus’ mother with His brothers. If they were His cousins, or the sons of Joseph from a previous marriage, why were they mentioned with Mary so often? The idea of the perpetual virginity of Mary cannot be drawn from Scripture. It must be forced on Scripture, in contradiction to what the Scriptures clearly state’.