Not an attack, not at all.
But I don't see how her having a sexual relationship with her loving husband is somehow corrupting her in any way.
And aren't there ambiguous scriptural reference(s) to siblings of Jesus, too?
I am a practicing catholic, and honor Mary, and accept both her Immaculate Conception and the virgin birth. That being said, I don't see why any of that inexorably leads to a conclusion that she remained a virgin after the virgin birth.
OK, bear with me as I post scriptual references to virginity as being the more perfect state. The implication being that if it is for the rest of us, it was most certainly for the Blessed Mother.
And aren't there ambiguous scriptural reference(s) to siblings of Jesus, too?
Aramaic uses the eqivalent of "kin" and apllies it to cousins as well as siblings. These are the references you mean, as to the Apsotle St. James the Lesser, the cousin of Christ, who later became the first bishop of Jerusalem.
As for Catholic practice, the ancient prayer of the Confiteor" "I confess, to Almighty God, to blessed Mary ever virgin, to blessed Michael the archangel,...."
Don't you think, even as just a practical matter, that subsequent marital relations would cause the supernatural origin of Christ to be questioned?