Is there a scriptural support that Mary was always a virgin?
There are also numerous citations by Our Lord in the Gospels, by St. Paul in the Epistles, as well as other OT & NT passafes praising virginity as the most desired state if one can keep it.
The Blessed Virgin Mary was also as St. Luke relates in the gopsel of the angelic salutation, "Full of grace", "gratia plena", "kerataow", in the Greek the most emphatic of the three. In other words without the stain of original sin, being preserved from the moment of her conception by the foreshadowing of the Redemptive Sacrifce of her Divine Son. Therefore the concupiscence of the flesh and spirit that afflicts the rest of us had no hold at all on her and she was the most chaste and perfect tabernacle to safeguard the Most Precious and Holy Son of the Father.
What amkes you think, after all of that, that the Father would ever permit the Holy Tabernacle of Mary to be corrupted or tainted in any way???
Attacks against the Blessed Virgin Mary in this regard become direct blasphemies on God the Almighty Father.