suggeting he ends his marriage just because she has a different view on the Bible. - ExBethelitenowPIMA
It's not about view point, its about who he is and who she is!
The OP said that he got into a heated argument with his wife on the idea that a JW can have a relationship with a non-JW. This is exactly what their own relationship is. Take away religion, let's use politics instead: A Republican father had a heated argument with his Democrat wife because she believes that their son will not be happy if he is with a Republican woman. How about this: "I'm an African, my wife and I fell in love when I was on a trip to America, but the other day, I heard my wife tell our kid that he won't be happy unless he marries a white American girl."
Am I starting to make some sense? How can you insist that a relationship is doomed to failure if your own couple is the living proof of the opposite? Unless she feels that the only reason she remains married is out of faithfulness to JW's standards of upholding a marriage, even if it means being unhappy for the rest of your life.
I believe that marriage is sacred, and you should work very, very hard to make it work. Constant communication, faithfulness, love, tenderness, all that jazz. But if you try all this and, after several years, the prevailing feeling is that there is no love, only commitment, no happiness, only obligations, then you are wasting your life away.
Let's assume here that the OPs marriage is just fine. They are both happy and and in love. Considering this, how can his wife have a "firm conviction" against interfaith relationships. If her point of view was, "Listen, if both believe in the same religion, it will be easier...", yes, she does have a point! But to be "firmly" against it when she, herself, is living in this sort of arrangement goes against the reality experience by both her and her husband.