@Alon @mekkaokereke and it's a rather logical argument that married couples vote similarly.
I'd never have married my wife in the first place if we didn't align (somewhat) politically. We're both green/left. I see no reason why the opposite should be true for people on the other side of the political spectrum.
There *are* couples with different values, sure. How likely is it they're going to vote in the first place? Or that they're making informed choices instead of "Daddy always voted D/R/I"?