It was common practice that there was a period of “betrothal” (usually one year) and then the bridegroom took his betrothed as his wife and the marriage was consummated. This was done for several reasons but the one in question here was to ensure the bride was a virgin and not pregnant with another man’s child. The bill of divorce Joseph contemplated giving Mary was because she was found with child before they were come together. I thought you already knew this verga.
Perhaps you should read the article, that was covered.