Not everyone needs -- or wants -- to say, "I do." The author of I Don't Know: In Praise of Admitting Ignorance (Except When You Shouldn't) explains why.

By Leah Hager Cohen

1. Because not-married doesn't mean all alone.

If you're married, it's generally assumed you'll always have somebody -- for better or worse. But I'd just like to say that when you're not married, you'll also always have somebody for better or worse, somebody to count on, love, laugh with, fight with, miss, confide in and rely on. Because being not-married doesn't mean you're alone. It means you're living your life with friends, lovers, sisters, brothers, neighbors and co-workers. You're just not living with a spouse. Maybe you're dating. Maybe you're in a relationship for two years, then in another for five years. Maybe you're like me: in a relationship for a decade and aiming for life. Maybe you opt for no romantic partner at all. Instead you connect with friends over big pots of soup and crusty bread, go on road trips and encounter strangers, work for social causes, swim in the ocean, play the violin in an amateur string quartet. You don't need to be married to have all the things marriage is supposed to give you -- a life rich with experience and intimacy.

2. Because love is a mystery…

And marriage, by definition, is a contract, plain and simple. I neither want nor need my love defined in business or legal terms. The beauty of love is that it's undefined to begin with -- and always changing.

3. Because real security comes from being known for who you are and cared for no matter what.

Upsetting stuff in life happens, and marriage doesn't stop it. Security, on the other hand, makes those rough times endurable. I get mine from my children, every time they crack me up by serenading our mutt with their improvised blues songs. I get it from my partner, every time he reads my mind and knows I'm craving a late-night snack of kettle-cooked potato chips -- and then whips out a package he just happened to buy on his way home from work. I get it from my best friend, every time she senses I'm burnt out and takes me kayaking or mails me a poem. Feeling known and adored by the people around you -- be they lovers or co-workers or chums -- provides the greatest security of all. And you don't need a spouse to rely on it.

4. Because you can still have the ring.

When one of my friends turned 40, she registered for a bunch of household items and threw herself an unbridal shower. At first, I thought this seemed weird and kind of selfish, but then it hit me: I'd never begrudged my betrothed friends their waffle irons, blenders and cute, little sugar spoons. Why should I want any less for my unmarried friends? For that matter, why not want these things for myself? Not housewares, exactly, but those aspects of marriage rituals--be they weddings or anniversaries--that do resonate with me. Because it turned out, after my boyfriend and I had been together five years, I found myself yearning for something surprisingly traditional: a tangible symbol of our connection, something I could have with me at all times, something I could touch. I shyly announced I'd like a ring, and he went out and found me a beauty. It looks like fairies made it from twigs and moonlight: tiny and bumpy with little specks that wink in the sun.

5. Because you can break up.

My boyfriend and I have been together 10 years now, and whenever we've hit an especially rocky patch (as all couples do) it's been a relief to know there's nothing holding us together except our desire to make it work. We're at liberty to break up in an instant if things become unbearable. What sweet, paradoxically empowering knowledge this is! During our saddest, ugliest, most hopeless moments, I have taken comfort in this fact, which has given me the willingness to re-dedicate myself to us.

6. Because you can always get married next year. Or the next. Or the year after that.

I'm no anti-marriage crusader. And this isn't an injunction; it's just a list. I was married once, and the truth is, my boyfriend and I haven't ruled out getting married someday. We're not sure what might prompt us to desire legal accreditation, but we remain open to the possibility. In a way, that's the whole point: remaining open. Both in our attitude toward marriage and in our relationship itself; we hope to stay open, to be continually receptive to ideas, to thoughts, to feelings, to experiences, to others and to ourselves. It doesn't matter whether you're in a long-term relationship, grieving the end of one, just starting a new romance or contentedly flying solo: None of us knows what the future will hold. And so we let ourselves move forward into it, clear-eyed about the limits of our certainty and invigorated by the adventure.

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