That might have helped, too.
As for me: the biggest similarity my husband and I have is that we both traveled a lot and had lived in several different foreign countries, and thought that was a great way to live. I posted the list of places I've lived on one of the threads here, and someone said it was impressive. Well, take those foreign countries, subtract west Africa, add South Africa plus Hong Kong, and you've got my husband.
Neither of my sisters moved more than 10 miles from where we grew up, although both of them have traveled a fair amount, they take a trip together to NYC about once a year to see plays, shop, etc. They're not provincial, in other words. But in their heart of hearts, they both think, I'm quite sure, that the way my husband and I used to live would not be for them in the slightest.
That was a big, big thing to have in common. Neither of us would have married a "stay where you were born" sort of person.
Beyond that, we are similar, but not identical, in political and religious views, similar in education and intelligence, very dissimilar in choices of reading, sports we like, etc. He's an engineer, I'm more of a foreign and public policy sort of person; we both enjoy language arts, good writing, beautiful language generally.
It's interesting what can bring people together and keep people together. There are as many ways to look at is as there are couples, pretty much.
Edited to add: one of the most important things for us: we both like dogs and don't particularly care for cats! Now THERE's a good reason to stay together - we would never be able to decide custody of the dogs.