Sorry, not so. The dogma of the Perpetual Virginity was promulgated by the Council of Chalcedon in 451 AD, and so is binding on all Roman Catholics.
Excuse me but I find these two statements too Western for my taste:
"the idea of Theotokos was developed..."
"The dogma of the Perpetual Virginity was promulgated by the Council of Chalcedon in 451 AD."
Neither statement is true from the Orthodox point of view. The entire Gospel of Jesus Christ, i.e. everything the Orthodox believe as Christians, was "once delivered to the saints"(Jude3). I repeat, "ONCE delivered". Not developed, not fixed up, not improved, not noodled with, not polished, not adjusted, not fine tuned. And that includes our belief that our gracious Lady, the ever-virgin Mary, is the Holy Theotokos and that she was a virgin from the day of her birth to the day of her falling asleep in the Lord.
The Councils did not promulgate new doctrine. They confirmed what was already firmly believed in the face of the Arian and Nestorian heresies.