That said (and you knew there was a disclaimer, right?) there are certain ingredients most relationships need to have a reasonable chance of succeeding. And the fact that you're so worried about yours makes me worry about it, too. (It also makes me think you're smart. If everyone thought this hard before saying "I do," maybe half the marriages in this country wouldn't end in divorce.) It's fine not to read all the same books (frankly, I'd worry if you did). But let me ask: Is there another hobby he might have—building large installations, programming small gadgets—that makes him interesting in other ways? I'm not sure what you mean by not having the same cultural references, but if it means you're well educated or from wealth while he's a simple guy from Podunk... again, not saying it can't work, but it's a definite obstacle.
To me, compatibility is huge—less intellectually, perhaps, than in terms of sensibility. Do you respect the way the other sees things? Do you make each other laugh? Do you light up when you see him? If so, who cares if you read Proust while he struggles to decipher TV Guide? But if not, it might be time to get on with your search for Mr. Right.
His take: Look, I'm a big fan of marriage, but here's the thing: Once you're married, and especially once you have children, how you treat each other may begin to slide. Maybe your boyfriend will be the sort who bucks the trend, and continues to treat you "like gold" until death do you part. But for many men, the courtship, however sincere it may be, is first and foremost about attracting the mate.
So the way he acts pre-marriage is not necessarily the way he will act post. I'm not suggesting that some Jekyll-and-Hyde-like transformation will take place. It's more that he could slip from Jekyll, who bought you flowers and chocolate every week, to Jekyll Lite, who's still a good guy but doesn't necessarily have the energy to continue wooing you now that you're both blessed with jobs, a mortgage, kids, and spreading waistlines.
All of which is to say: Intellectual compatibility matters. Because if and when the gold treatment does start to fade, you'll still have the same ironic sense of humor to share, the same books to discuss, the same opinion of global warming to chew over. It's not that you have to have the same taste in food, art, or home decor. But having large tracts of overlapping brain and soul can save and enrich a marriage more than all the flowers and chocolate in France. And being so in sync that your interests, tastes, and opinions are able to change and evolve together—without leaving the other person behind—is what will make your marriage last.
For the best advice on sex, love, dating and relationships we ask two experts with personal experience. Cathi Hanauer is the author, most recently, of Sweet Ruin, a novel about love, marriage, and adultery. Daniel Jones is the editor of both the "Modern Love" column for The New York Times, and Modern Love, an anthology derived from the column. They've been married for 15 years, and together they provide a his and hers take on relationship questions. This round: intelligence inequality.