That is absolutely false.
Who told you that?
Do you teach that to those you instruct? If so, and if you are interested in truth --- then you really should stop repeating such erroneous information. You've been provided enough information ---even recently--- to have precluded yourself making the above italicised statement.
Jerome (237-420 AD) who was the eminent scholar of his day, considered Helvidius' claim "novel" and shocking. I conclude that he thought of Helvidius' denial of the ever-virginity of Mary as an innovation.
If this is false, then tell me what churchman before Helvidius claimed that Mary, specifically, had other children, or that someone (other than Jesus) was called "son of Mary".
I'll be grateful for a link. I'll follow any link you supply.