But if we have to make up a couple of possible explanations (because Scripture is not explicit on the question), why don’t we just assume that after Christ was born, Mary had other children the regular way? I can’t see how that taints her special calling from God to be the mother of the Messiah. I’m not arguing just to argue, I can’t see why it’s so important to maintain her virginity when Scripture doesn’t explicitly support it. It does not detract one whit from her status, IMHO.
The tradition that Joseph was married before and had children is not "made up" in the sense that somebody thought it up recently. Like the perpetual virginity of Mary, it's a very long standing tradition (though not as important or as universal).
I know that there's a tendency for Bible-centered believers to think that every tradition not explicitly founded on the Bible is 'made up' and hence worthless, but unless you acknowledge some tradition, you don't even have a Bible. And of course the Bible itself (especially in the letters of St. Paul) assumes and refers to an ongoing tradition existing outside of and side by side with the written word. And that tradition exists in unbroken continuity from the Apostles to the present day.
Remember that until the rise of the middle class in the 16th and 17th centuries, most people couldn't read. The only way they got their religious instruction was through the teaching tradition of the Church.
There is a tendency for those who put the Bible first to ignore the many centuries when (a) there was no Bible; and (b) nobody could read it even if they had one. So if the Bible is all there is, there is a break in continuity that lasts about 1400 years. Not good. And think of all those people who were lost because they didn't have a Bible . . . not good.
If you simply acknowledge the traditions that were maintained by all believers, Catholic and Protestant, until very recently (mostly, the 19th century, the German theologians started it and the popular Evangelicals like Moody and Sankey continued it), then the problem is solved. Not to denigrate Scripture at all, but it does not and cannot exist in a vacuum.