Let's not kid ourselves. We live in the 21st century. Maybe you already live together, split bills, and have sex. So. How will marriage change all this? Find out.

Let me guess. You and your (potential) fiancée live in separate houses-she still lives with her parents, learning how to be a housewife-and you're both waiting for you wedding night to have sex, right?

If that's you- move on. The vast majority of this site will offend you deeply.

If you're like 68% of couples today, then you've already shacked up and are living in sin. So what, if anything, actually changes when you get married?

Gaze into The Plunge's crystal ball:

Different: Less socializing. The number of restaurants, bars, and lounges you go to will plummet by 20-60%. And when you do (grudgingly) leave the house to meet friends, you'll go home 90 minutes earlier than before.

Same (or better): The sex. You can relax about this one. From watching American Beauty or every sitcom, you'd think that once you get hitched, the highlight of your sex life is a morning jerk-off in the shower. Don't worry. That won't happen when you get married...that will happen when you have kids.

Different: More nesting. That gift registry serves a purpose--now that the two of you are literally a family, even if you've already lived together, you'll still find yourselves doing more cooking, watching more Netflix, and spending more time "playing house." This isn't a conscious decision, but something that you'll slip into, gradually, the way a heroin addict eventually needs a bigger and bigger hit. Soon you won't remember a lifewithout your domestic heroin.

Same: Her. She won't morph into some wretched nagging wife, and she won't be cleansed of all her annoying quirks. What you have is what you get. (For more on seeing if she's The One, click here.)

Different: The way you buy goodies. In the old days, let's say you're in Best Buy and have an epiphany-you realize that your 5 megapixel camera is suddenly laughably inadequate, you need 8 megapixels, 10 megapixels, you'll go 50 megapixels if possible. You need it, you must have it, it's a minor miracle that you got this far in life without it. So you pull the trigger... Once you're married? Every purchase over X dollars (where X is between 20 and 200, depending on your income) needs approval from both chambers of Congress. This is the biggie. Until you have kids, money will be the root cause of all tension and bickering. It's the one thing that living together can't prepare you for. Where to invest? Do we splurge for the convertible? Can I buy the new iPhone? These are no longer your decisions. If you've lived together you've probably discussed money and agreed upon some broad contours-where to live, when you'll buy a house, etc.-but marriage is a different ballgame. It's not (necessarily) miserable. But it's different.

Same: She's still not going to understand why the NFL Draft is must-see TV, why a playoff game from 2006 is still flagged on your DVR as "never erase," or why you root for the Dolphins' kicker in a 30-point blowout. Marriage brings you closer...but it's not a mind-meld.

Different: The home décor. For her, marriage is the difference between a house and a home. As a live-in girlfriend, she was cool with the Yao Ming lamp in the bedroom. As a wife, she'll have less tolerance for a décor that's inspired by 7'6" Chinese centers.

Same: Your global routine. While you stay in more and bar-hop less, it's true that the overall arc of your habits will remain the same. Your jobs are the same. Your tv watching is the same. So for a good chunk of your everyday experience, living together is a fair approximation of what the future will hold.

Different: The chores. It's a subtle shift, but now that the courtship is officially over, no one needs to impress the other, so she's less prone to doing the "guy chores" like yardwork and trash. (And vice versa.) Right or wrong, gender stereotypes exist for a reason, and you'll find yourself sliding into those norms.

Same: Your chemistry. Either you have it or you don't. Marriage isn't a panacea that will suddenly inject morechemistry into a relationship, but it's not going to suck it away, either...at least not yet.

Different: The in-laws. Today they keep their distance. But the moment that you become family they could "pop in" whenever they please, expect more invitations, hound you about the holidays, and potentially visit for weeks at a time. The secret is to create boundaries, and that starts right now, today, before you get married. Click here to find out how.

If and when you're ready to pop the question, don't skip our 10 Commandments.

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