Joseph's Willingness to "Put Away" Mary

In the Christmas story, Mary is pregnant with Jesus on a trip from Nazareth to Bethlehem to pay some taxes there in that ancestral town. Earlier and according to Matthew 1:18-25, Joseph understandably thought Mary fornicated with another man other than himself. He knew it wasn’t himself, because he had not “known” her. Joseph had not fornicated with her (premarital sex), but someone else had, which was why she was pregnant. At that juncture, Joseph will willing to “put away” Mary secretly. He wasn’t going to bring more public shame upon her than she was already receiving, partly because he was a just man.

Questions: how was removing or avoiding rightful, just shame for Mary a righteous thing? Doesn’t that just encourage more sexual sin? Just the opposite. One, he likely witnessed and assessed her shame in their small hometown. Two, he was putting her away, that is, divorcing her. In that era and culture, one divorced during engagement or betrothal. Betrothal brought an identification of marriage.

Matthew 1 calls Joseph, “her husband,” and she, his “wife” during espousal. However, this was still premarital and, thus, “fornication.” This is a major reason why the exception clause for divorce in Matthew 5:32 and 19:9, the only two places the singular noun, “fornication,” occurs in Matthew. The word “fornications” (pre-marital) contrasts with “adultery” (post-marital) in Matthew 15:19. Jesus is saying, no exception except for betrothal period – in line with Joseph’s decision. After marriage, what God has put together, let no man put asunder.