I'm really sorry you are undergoing this.
Maybe you can share with her the July 2009 Awake, page 22, which says, " No one should be forced to worship in a way that he finds unacceptable or be made to choose between his beliefs and his family. Does study of the Bible read to family breakups? No. In fact, the Bible encourages a husband and wife who practice difference religions to remain together as a family."
Ask her if she believes this. Tell her you made a vow to God and do not intend to break it.