Jesus was not married to His disciple Mary Magdalene; He never married another person, but the church is His bride. Jesus never had children.
The early church was not covering up the truth, but protecting the truth that Jesus is God the Son. 
Brown falsely claims that religion was originally matriarchal. He even errs on the date of the Dead Sea Scrolls. His claim that "All descriptions of artwork, architecture, documents, and secret rituals in this novel are accurate" is a lie. One of his characters claims without evidence that there were 80 gospels out of which Matthew, Luke, John, and Mark were chosen. Constantine did not choose the canon. Brown falsely claims that Christianity copied Mithraism, and that the deity Mithras died, was buried in a rock tomb, and resurrected in three days.
Dan Brown says that "early Jewish tradition involved ritualistic sex" in the Jewish Temple, and that Jews worshipped the goddess Shekinah in addition to Yahweh.
The DaVinci Code contains dozens of other discredited claims beyond the scope of this post and is not worth the money.