Scott Adams at The Dilbert Blog:
The biggest relationship mistake you can make is to assume that because you have some special training or knowledge on a topic, that your opinion should be extra important. You could be the world’s most respected expert on insects, for example, but if your mate insists that caterpillars grow into chipmunks, there will be no talking him or her out of it...(This works well if one partner doesn't care much...)
So forget about how much you know, or how smart you think you are, or how much extra information you might have recently collected. That will not help you. Instead, I offer you the only solution: The WCM Method.
WCM stands for Who Cares Most. If you want your relationship to have a chance, defer all decisions and interpretations of fact to the person who cares the most...