Let's stick to your original claim which I refuted with Scripture.
She did not have any other children. "Brothers" of Christ are indeed mentioned, but, curious thing, every time a "brother" of Jesus is mentioned by name, his mother also is mentioned and she is not Mary.
MATTHEW - NAB
13:55 Is he not the carpenter's son? Is not his mother named Mary and his brothers James, Joseph, Simon, and Judas?
Brothers of Christ are listed and His mother is Mary
One thing at a time please.
1. Defend your claim.
2. Then divert to the standard Apologetics merry-go-round.
You will not get anywhere arguing with those who validate their own arguments. Absent any standard or authority other than their own whims each is his own each is his own denomination, each is his own pope and each his own magisterium relying on notions confused with the indwelling of the Holy Spirit.
As Ayn Rand so accurately stated: “[An] error is committed by the man who declares that since man must be guided by his own independent judgment, any action he chooses to take is moral if he chooses it. One’s own independent judgment is the means by which one must choose his actions, but it is not a moral criterion nor a moral validation: only reference to a demonstrable principle can validate one’s choices.”
And there were also women looking on afar off: among whom was Mary Magdalen, and Mary the mother of James the less and of Joseph, and Salome: (Mk 15:40 )
It is a Mary allright, but a different one.