Was Joseph married before marrying Mary? Why was he married to Mary?
The apocryphal writings present the story of Joseph’s marriage. These writings are non-canonical books. So, they may be true or mythical. However, they help us connect the gaps in the Biblical narratives. According to the Apocrypha, when Joseph was 40 years old, he married Salome (Melcha or Escha). They lived together for 49 years and had four sons and two daughters. The youngest was James the Less, also known as “the Lord’s brother”.
This story helps us to understand the brothers and sisters of Jesus mentioned in the gospels (Mk 6:3; Mt 13:55-56). “A year after his wife’s death, as the priests announced through Judaea that they wished to find in the tribe of Judah a respectable man to espouse Mary, then twelve to fourteen years of age. Joseph, who was at the time ninety years old, went up to Jerusalem among the candidates; a miracle manifested the choice God had made of Joseph, and two years later the Annunciation took place.” (http://www.newadvent.org/cathen/08504a.htm). Joseph’s role, though married to Mary, was to protect her life and her virginity. However, God called him also as the Redeemer’s foster father.