Single life is a series of challenges. But the one that leaves me breathless — even as I write this — is the supersize challenge to be undependent (whole) during unpartnered phases and (gasp) retain a sense of self while coupled. And no, that's not an impossible dream. (Radical, perhaps, but eminently doable.) What it takes is conscious and constant vigilance.

The payoff is huge. Long-term lovers agree that individuality keeps the spark alive, nourishing mutual respect and adding to the joy of togetherness. And frankly, I can't imagine a more thrilling game plan. Here you are, definitely not a blob, and you meet someone who fits a very special niche in your life. But in the middle of joyous discovery, there is the nagging question of how to keep this going for a very long time. The angel on your right shoulder whispers, "Game playing is absolutely prohibited." And the savvy single listens.

It's so easy to slip into old ways, talking for granted the precious wish fulfilled. You've been with couples whose line of communication has consisted of sly, underhanded barbs, a form of guerrilla warfare making everyone around them more than a little uncomfortable. A male friend of mine warned me to be careful with a beloved, and that word stays with me still. It's the one-word formula for lasting love because it includes so much — respect, friendship, quiet loving. Sounds great. But can it be sustained?

A resounding yes from this corner — provided, of course, the two of you hold on to your individuality. And hang on for dear life. (It truly is the mainstay of a dear life!) Yes, we're back to that other magic word, individuality. So many of us females, I admit, promise ourselves we'll surrender our individuality when we merge. We do it in the name of love, of course; deep in our DNA is the sadly mistaken belief that being authentic amounts to selfishness. Which is, so goes the fiction, the kiss of death for true love. One of the partners — usually female — proceeds to melt into a shapeless goo that hides the person's self and bores the other partner. Not exactly a formula for love eternal.

So, dear ones, the assignment — should you care to accept it — is to be mindful at all times of your personhood. Not the usual homework, it requires ongoing awareness of being more than another "single" and being the most you can be. Which means not bowing to the usual limitations of being solo, making singleness incidental rather than the centerpiece of our life.

Then again, most of us want to be coupled. That's a primal push, but these days, it takes another twist. Lovers around the globe are eschewing marriage for another form of connectedness, less formal but in no way less committed. Cohabiters are the fastest-growing segment of the marriage-age generations because they do value their personhood — but also want family and love. So they've come up with a hybrid: family and individualism. In this new form of togetherness, they usually keep their maiden names, individual bank accounts, friends and interests. Many European governments have names for the hybrid, "civil partnership" being one. These relationships can come with pension rights, inheritance rights and hospital visitation rights. They are the result of new ways to commit to a love partner. It's way too soon to judge their success, but as social mores shift, it's a given that legalities will follow suit.

Best keep your dual passport — for the single and coupled worlds — up-to-date for a lifetime.

Have a question for Susan? You can reach her directly at [email protected].