Islam is more of a way of living than religion. What happens here is marriage takes place both way.
don't forget the story: a Sahaba asked our beloved Prophet Muhammad (s.a.a.w) that he needed to break relation with his parents as they were non-muslims. He said he must keep in touch and take care of them. What do you learn from it ?
he preferred relationship over religion, don't forget his biggest companion was his uncle who was non-muslim.
we need to study Islam, it says more things than it meets the eye