[RnMomof7]

Is it really the first time you ask me this? I handled this question half a dozen times on this thread alone. It would not be in the least sinful for Mary to have marital relations with St. Joseph. She remained virgin because she chose to; there was no obligation on her to do so.

How does the church know she stayed a virgin?

The answer is they do not.. This "tradition" is passed down from people that believed sex would somehow soil her.. make her human.

What I think is most noteworthy of the claim by the Roman church that Mary was a perpetual virgin is that it just does not matter..

The state of Mary's sex life has nothing to do with our salvation . She is not our savior, her sins have no impact on our salvation . She was a real flesh and blood human woman, there is not one thing in the plan of salvation that demanded she remain a virgin ..

[annalex]

This "tradition" is passed down from people that believed sex would somehow soil her

How would sex with her lawful husband "soil her"? We have plenty of saints who were married with children.