I have been married six years, which is not very long, but long enough to get me out of newlywed territory and into the conviction that I can speak with some authority on the subject. So let me tell you: Your soulmate does not exist. (And even if they did — which they don't — you would almost certainly never find them.)

I mention this for those who remain single to search for their mythical soulmate. Yet it is maybe even more important for others who have dated for years, deferring marriage indefinitely in favor of cohabitation in an effort to be sure their partner is really and truly perfect for them.

But no one is perfect — for you or anyone else.

This is why living together before marriage is not necessary for any practical reason. (There are other reasons to avoid it too, from religion and social science alike, but that's another column.) Often, cohabitating couples believe they are being wise and responsible — that living together before marriage will give them a chance to investigate up close whether their partner is really the best possible fit.

This isn't rational and smart. It's foolishly romantic.

The chief reason given for living together before marriage is compatibility. Cohabitation allows each partner to take a microscope to the other’s domestic, sexual, and financial habits. More than half of couples who cohabitate cite this as their top rationale.

"It's really a practice run for a lifetime of living together," a Brides magazine listicle on the subject chirps. "If you're a total neat freak and your partner isn't quite so bothered by things piling up here and there or leaving dishes in the sink for a few days, sharing living quarters will help you figure out how to make it work and whether the two of you can handle it."

Living together is also often cast as a means of obtaining certainty about oneself. "I'm still figuring out so many things," explains Julianne Simson, 24, one half of a "typical" cohabitating couple profiled by The New York Times. "I'll get married when my life is more in order," she adds. "Since marriage is a partnership, I'd like to know who I am and what I'm able to offer financially and how stable I am, before I'm committed legally to someone."

These two assumptions — that before we marry we must know everything about our partner and have everything about ourselves sorted out too — are nonsense. They rest on fundamental misunderstandings of marriage, giving it at once far too much and far too little concern.

First, there is nothing you need to know before marriage that can only be learned by cohabitation. Do you have questions about your partner's financial habits? Ask them. If they will not tell you all you need to know, you have a problem that living together can't fix. Do you suspect you and your partner have different standards of cleanliness? Talk about it. Talk to their roommates. Visit their parents' house and see how clean it is. These and any other questions about daily life are not that difficult to settle. Any basic premarital counseling (or even a good list-based discussion) will cover this stuff.

But the compatibility testing living together is supposed to achieve isn't really about collecting information. It's about whether we like what we find. Cohabitation says, "I like a lot of things about this person, and maybe if I find out I like everything, I'll stick around." It is an arrangement, not a commitment. Marriage is made of stronger stuff. It says, "I like a lot of things about this person, and I'm committed to the sometimes difficult work of living with and loving them even if it turns out I don't like everything."

Contrary to conventional wisdom, the latter approach is the more practical, because the mutual inquisition living together entails is a fool's errand. It seeks a romantic perfection that does not exist. It buys into the myth of the soulmate, that there is one perfect person out there for each of us, a magical someone who fits our every whim. That's juvenile nonsense bordering on delusional, and a sure route to dissatisfaction. Expecting this sort of perfection puts marriage on an absurd pedestal — we may feel it unattainable or experience our entirely acceptable relationship as "settling" — and yet simultaneously devalues it by delay.

Marriage is more mundane than all that. It's fine to find out after the wedding that your spouse has some irritating quirk. That's not a reason to put off commitment with all this endless dithering about compatibility. It's okay if you don't have a grand or unique love story. Most of us don't. It's totally normal to be married to someone who doesn't share your views on housework. I am, and we bicker about it sometimes, and then we might bicker about how different our bickering styles are, and none of this is a big deal. The idea of ending my marriage over dishes is so stupid I can't even contemplate it. Were my husband twice as messy as he is, we'd still be just as married as we are.

Perfect compatibility is neither possible nor necessary for a healthy and successful relationship, but the durable commitment marriage requires (and cohabitation lacks) most certainly is. And just as it is unreasonable to expect to know and like everything about your partner, so you cannot expect to fully know yourself as a precursor to marriage. Total self-realization is not a condition of commitment. Marriage does not require you to have everything figured out, merely that you are willing to do the figuring together.

You grow with your spouse, because the wedding is not an end point of personal development. You meld your lives together, each facilitating the other's wins and cushioning their losses. The sooner you commit to the mundane trials and pleasures of marriage, the more compatible you and your partner will become.