Tough topic to answer. Yes, sexual romance changes over time. But that is different than what you describe in your marriage. In order for your wife to have gotten to the point she is at, an event or an awareness most likely occured that she could not either discuss with you or resolve by herself. Marriage is hard work. Both people have to work at it as the marriage will fail if both people do not do this. Somewhere along the way she probably stopped having faith in communicating. There is a lot more to it than having a relationship with out sex. There can be sex without a relationship, but you can't have intimacy without communication.