Most of us were brought up to believe there was a single entity called a Good Husband. Yet there are actually two very different kinds of good husbands: the Boyfriend and the Husband.

The former is everything you've wanted since you were 15: sexy, spontaneous, irresistible. He makes you laugh, makes you shiver, makes you mad as hell. The thing is, he never quite pictured himself as a husband and father, and deep down he still doesn't. When you're trying to explain the concept of equal parenting or picking up his wet towels from the floor, you wonder: Did I make the biggest mistake of my life?

The Husband is your best buddy, a man you can count on to walk the baby at 3 a.m., research Consumer Reports for the safest car, and even buy you tampons on the way home. Yes, sex is more tender than thrilling, but isn't that to be expected with time? Still, sometimes you wonder if this cozy security is all it's cracked up to be. Shouldn't marriage have more pizzazz, electricity, mystery?

Well, yes. And Boyfriend husbands should stay home more often, too. But just as there is no one good marriage, there is no one good husband: Even the best have a B side. But how do you live with your doubts and still love and nourish the good marriage you've got? Read on to find your kind of guy, and the road to happiness with him.

From the outside looking in, we all envy the Boyfriend Marriage — and from the inside out, it does feel as good as it looks. Romantic. Spontaneous. Magical. Right. "At its best, it feels the way you were always told marriage should feel," says psychologist Judith Sills, Ph.D. No matter what else is going on — kids, work, family — the marriage itself is always front and center.

"Our relationship is intense and has been from the very first minute," says Jane. "Kenny is a guy's guy. I love that he loves fast cars, that he finds the female psyche a complete mystery, that he hates to wear a tie. At the same time, I feel he knows me in a completely visceral way. I couldn't have married a 'best friend' kind of man. I wanted to be swept away, and I was."

Eight years and two kids later, the intensity is still there — in and out of bed. Theirs is a rollickingly connected kind of marriage, like a radio that never gets turned off. They're on each other's frequency all the time. And that's wonderful when the magic is working. "But these days, to be honest? I'd rather be sleeping than making love," says Jane.

Kenny doesn't understand this, which can sometimes lead to arguments. "Of course he doesn't understand," says Jane. "We both work long hours, but I'm the one who's on kid duty. So when he's raring to go, I'm in meltdown mode." Sometimes, though, the situation is reversed: Jane will want his attention at a time when he's too busy and he'll be dismissive, which can also lead to fights. "When you start out that passionate, there's an expectation level that gets established. You're both accustomed to getting a certain amount of attention, and when you don't get it or can't give it, feelings get hurt."

Indeed, if the highs are higher in this marriage, the lows are also lower. "I adore my marriage 80 percent of the time, but a lot of the time it's exhausting. We each register every little disturbance," says Jane. "Sometimes I'd like to forget about my relationship with Kenny for a while, to be a little less in love."

Passion — the glue of the Boyfriend Marriage — has a downside, and it resides in its very origin: The flame that fuels it is either unfamiliarity or uncertainty. And much as we love our husbands, they do not remain an endless series of brand-new revelations. Which leaves us uncertainty: Maybe you've got a mortgage and a station wagon now, but the dynamics haven't changed much since your dating days. The same questions still rivet you, just beneath the surface of your everyday lives: How does he feel? How do you feel? Is he still attracted to you? Do you still love him?

Most of the time, you don't feel the uncertainty, just the pleasant fizz it gives off, the way your heart jumps when you first catch sight of him, the way you feel walking into a room together, the rightness. Then something happens, and the balance tips — and you're back in the land of does-he-or-doesn't-he? "To feel rejected by the most important person on a pretty consistent basis can wear away one's spirit and sense of self," says Dr. Sills. "When uncertainty is what is sustaining the passion, that can feel like an ordeal."