The collective you, if you haven’t figured it out, is who you become when you commit fully to a loving relationship. You are no longer just you. You are you and your girlfriend/fiancée/wife. Every decision, every action, every reaction, affects the whole, the entire unit of two. It’s a heavy thing, and a heavy decision. Not too dissimilar to buying a car, or a house, or any other big, bulky purchase that represents maturity and the dreaded specter of responsibility. This collective you is a very foreign concept for the single you. It’s new math. For years you only had to remember what “you” wanted. What do “you” want for dinner? Will “you” have another drink? Should “you” go to the gym or stay on the couch for another hour watching TV with no pants on?

What it comes down to: The collective you is simply superior to the singular you. Instinctually, we all know this, which is why we go out and seek it. True, you give up more than 50 percent of your living space to scented candles, throw pillows, and other useless cargo, but you gain the power of two.

Men’s egocentric thinking, combined with an overwhelming drive to be personally successful, gives them no time to consider the difference between the collective and the singular you. It doesn’t come up. Women, on the other hand, are smarter. They make the time. Yes, they strive to be successful, and, yes, your girl can veg on the couch with the best of them. But while you sit, one hand operating the TV remote with the dexterity of a brain surgeon and the other resting comfortably on her leg, screaming out Jeopardy answers to show her how smart you are, she is thinking, and thinking, and thinking. Not just about the collective you (she’s got to think about nail polish and unicorns sometime, right?), but it’s on her mental agenda.

To her, moving in together is a symbol that your relationship is going to another level. To her, the move is the penultimate, like Triple-A baseball—just one short step from the big leagues and wedding bells. You look upon cohabitation with more practical sensibilities: you only have to pay half the rent; all of your clothes are in one place; sex is not a matter of “if” but “when”; and there is always someone to help you take off your shoes when you come home drunk.

There are definitely times when you want to flee to something dirty and familiar—you might even think you are smart enough to pull it off. Forget it. You’re not. If you were smart in the selection process, she is smarter. So don’t think for a second that you can have it both ways. You have to abandon the hope of being what you once were. Instead, you must focus on the hope that this new thing you have signed on for somehow makes you a better person. After all, that’s why we play the game. And if you screw it up, you will truly know what hell is.

Now, when you come home from work, it takes a moment to remember that this is your place, with its jasmine potpourri and Restoration Hardware area rugs. Now the towels match. Now your CDs—Outkast, Led Zeppelin, and Britney Spears (it’s all right, we all have one)—share space with Tori Amos, Ani DiFranco, and the rest of the Lilith Fair Powder Puff Football Team. Now everything is put away in its “proper” place. Her photo albums—under the coffee table. Her clothes—in the bedroom closet, and the hallway closet. Your clothes—in whatever slim closet space remains, and under the bed. Your pictures—in a shoe box under your clothes.

Now your fridge is clean. That half-empty case of Bud has been replaced with a bottle of Sauvignon blanc, and the “crisper” drawer actually has fresh vegetables in it. Now you know what a “duvet cover” is.

Now the clock is ticking … Now the walls seem closer, the air feels thinner …