Wife and I are very similar and it works really well. Even when we don't have the same interest, we both enjoy learning about the other person so much that we like to partake in their adventures regardless of our interest in the topic at hand.
T and I have mostly different interests, but there's still an overlap in music, literature, social gatherings, and sex. I would guess that if we were actually around each other more often it would be more of a problem.
Me: 39 straight male in a V with
Wife: Kay - mono female - married 17 years
LDR girlfriend: Susan - poly female - 3 year relationship
Stakes - very intimate friend