Mary "served" Joseph in a "base way"? :) You really seem to have genuine disgust at the thought that Mary was a wife to her husband. Is your above indicative of your views of marital sex generally or only in this case?
We have given many verses that lean toward Mary bearing other children. The only responses I have seen were to discredit those verses. I have not seen any scriptural argument PROMOTING Mary's perpetual virginity. Perhaps there is a reason for that. :) As I read the scriptures, I only see marriage as being a positive and blessed institution. I do not see God approving of any sham marriages:
Matt. 19:6 : Wherefore they are no more twain, but one flesh. What therefore God hath joined together, let not man put asunder. (KJV)
I suppose the Apostolic interpretation of this verse would be that it doesn't say that God can't put it asunder. Or, that God can create a sham marriage if He wants to. I suppose that if God created it, He is free to wreck it also, but I don't see why He would have done this to people like Mary and Joseph.
I did not see it on this thread, but her statement "I know not man" in Luke 1 suggests that it was never the intention to consummate the marriage to Joseph in a sexual way. I recall discussing it on the Erasmus thread. That is because, normally, a woman engaged to be married does not react in utter surprise when she is told that she will bear a child.