I do believe that Henry truly believed that his marriage to Catherine was contrary to God's law (Leviticus 18:16) and that God was showing this by not blessing the couple with a living male heir. Although many people see it as a convenient excuse for Henry to leave Catherine and marry Anne, there is evidence that Henry was worrying about this Bible text and his marriage before he even met Anne. Henry believed that he was God's chosen, appointed and anointed monarch and therefore God should bless him with a male heir, so there must have been something wrong if a male heir was not forthcoming and it had to be the wife's fault, as the wife was descended from Eve and was always to blame in the case of miscarriages or sin within the marriage. It just couldn't be Henry!
I think that Henry also became paranoid about his second marriage when Anne had a girl followed by miscarriages and I think that left him open to being persuaded that Anne had to go.