I don't think that she should leave him. Yes he should have trusted her but that was his character- he has always treated his father like god. Priya knew this is how he would react. To expect him to react any different would'nt do justice to his character.
he definitely needs to make it up to her, work on earning her trust but in a marriage, trust is built by staying together and working it out together.. You cannot work on a relationship by being separate..
Marriage is work- hard work especially in tough times. This will help their relationship become stronger.
She shouldn't leave him, she should stay and have him earn back her trust.