Restore your sexual mojo with this get-some guide

You'd never guess that my client Lydia—who is beautiful, smart and funny—wasn't having sex as often as she'd like. Her husband, Harry, thought once a week was plenty, but Lydia wanted to do it every day. While she'd always been a little more hot to trot than he was, the gap—and ensuing tension—had only increased. "Don't men usually demand sex all the time?" she asked. "What's wrong with me?"

Julia had the opposite problem. She and Stuart had felt sexually compatible from the start, but with three children under 7, Julia had gone from being "slightly less aggressive" to far more interested in sleeping than making love. By the time they came to see me, Stuart and Julia hadn't done the deed in three months.

It's natural to fall a little out of step with your partner after you've been together for a while. Maybe—as in that famous scene from Annie Hall—the amount of sex you're having feels like a ton to you and nothing to him. Perhaps one of you wants to try something that the other isn't into, or suddenly it seems like there's nothing he can do to turn you on.

Here's a bit of biology: When you fall in love, your body releases the pleasure neurotransmitter dopamine. You're flying so high that attraction feels effortless, and since you want to please your new partner, it's fun to try new things out with him. But eventually your dopamine output dips to more normal levels as familiarity and friendship develop between the two of you over time. While these are very lovely qualities to have in a relationship, they can be directly at odds with desire.

Sometimes being out of sync is simply about being too damn busy for sex (like if one of you is returning home late from work and the other is crashing early) or about one person becoming the only instigator. Or you just experienced a hiccup (such as taking a break from romance after your kid was born) that grew into a bad habit. Whatever the reason, you've entered the Sexual Frustration Zone. Luckily, there's a way out.

1. Don't settle for just so-so

You might say to yourself, Sex isn't that important as long as we get along. But as I've seen in my practice, that's the case only when both members truly have zero interest in sex, which is fairly rare. What happens much more often is that one person says, "I'm fine with not having sex!" while the other person is not fine with it. At all. It's a situation that can actually lead to the demise of a relationship, even one that's strong in every other department, because the more in tune you are sexually, the more tools you have as a couple to right your ship during tough times—whether you're facing health scares, money woes or family drama.

2. Steal alone time

I can't emphasize this one enough! I know—it seems impossible. It's so worth it, though, to get a sitter—once a week, if you can—and have some relaxed fun with each other outside the bedroom to get those dopamine levels back up. This is the ideal time to raise the idea of trying new things, whether it's having sex somewhere besides the bedroom or upping the romance factor. Most men want to please, but they aren't mind readers, so be clear: "I'd like you to help me get the kids in bed so I have energy to rock your world afterward."

3. Check in with your MD

If you and your partner are still a little off-kilter in the intimacy department, there may be a medical issue—it could be anything from depression to diabetes or even heart disease—that's to blame. Taking medications such as (ironically) antidepressants can also blunt sex drive. And while a dip in testosterone levels is normal for men as they age, a big hormonal drop can lead to a loss of libido.

4. Talk it out

Maybe after trying all that, you just can't seem to get in the mood when he is. Or your ideas of fun still don't mesh: Do you looove foreplay while he always jumps straight into the main event? It never hurts to ask for help from a pro. Yes, opening up about your sexual frustrations can be hard, especially to a stranger. But a certified sex therapist can give you assignments designed to tackle the specific issues you two are having. She might suggest giving each other a massage with instructions not to have sex, for instance, to take away any pressure. Even chatting with a couples therapist can help you understand what's really at play. You may need only a few sessions to get back in step—both in the bedroom and out of it.