Love is perhaps our most powerful emotion, and the need to be in a loving relationship may be one of the strongest needs we have. Being in an intimate relationship makes us feel connected, not only to our partner, but also to the world at large. When our hearts are filled with love, we feel profoundly content and satisfied. We become more patient, more empathetic, kinder, gentler.

But personal intimacy doesn't merely affect our emotional well-being. According to numerous scientific studies, the power of love directly affects our physical health, too, by boosting our immune system, improving our cardiovascular functioning, and increasing our life expectancy. "Love and intimacy are at the root of what makes us sick and what makes us well," says Dean Ornish, M.D., who explores the connections between love and health in his book Love & Survival (HarperCollins). "When you look at the scientific data, the need for love and intimacy is as important and basic as eating, breathing, and sleeping."

On Valentine's Day, we celebrate our love for each other over candlelit dinners or through exchanges of chocolates, flowers, and slinky lingerie. But a box of bon-bons only lasts so long. Experts agree that the key to a vitalized, long-lasting relationship is what you and your partner do the other 364 days of the year. Indeed, keeping your love alive requires continual time and effort. Following are eight steps you can take to keep the flame burning.

1. Be Friends
Any healthy relationship must be based on a solid underlying friendship. Remember to treat your partner with the same kindness, respect, and appreciation as you would a close friend. Support, listen to, and laugh with each other. Don't allow yourselves to be rude or disrespectful.

2. Stay Connected
"Couples need to spend a lot of time with each other," advises David Kaplan, Ph.D., chair of the Department of Counselor Education and Rehabilitation programs at Emporia State University in Emporia, Kansas. "There is no substitute for quantity of time." Kaplan encourages couples to take a half-day a week to go out on a date. In addition, devote at least 15 minutes of your day to meaningful, one-on-one conversation — no television or kids allowed.

3. Get Physical
Physical intimacy is a natural, and healthy, extension of a relationship. Our best sexual intentions are often put to rest, however, as we collapse into an exhausted heap at the end of the day. Instead, you and your partner need to consciously commit to turning up the heat. Leave the dishes in the sink, turn the laptop off, and just do it! Set the mood with the sensual music, and light some calming aromatherapy candles or incense. Learn to communicate your loving energy through touch.

4. Celebrate Each Other
Saying something kind and affectionate to your partner should be a daily habit. The expression of loving thoughts nourishes your relationship by helping you both remember what it is you treasure about each other. Let your partner know how much you appreciate him or her, and be generous with compliments and expressions of affection.

5. Fight Well
Since disagreements and arguments are inevitable, what's important is not whether you fight but how you fight. When disagreements surface, keep them short. "No more than 10 minutes," says Kaplan. "After 10 minutes, it gets nasty and repetitive." Also, keep boundaries on the subject matter. Don't dredge up issues from last week or last month-keep your dispute focused on the matter at hand.

6. Take a Class
Feeling like your relationship could benefit from professional advice? Why not take a class on communications skills, attend a seminar on loving kindness, or read a book on relationship-building together? Your efforts will likely spark important discussions about your relationship and, ultimately, enhance it. A good starting point is Phillip McGraw, Ph.D.'s straight-talking tome Relationship Rescue (Hyperion, 2000).

7. Listen Carefully
Being an attentive listener lets your partner know that his or her thoughts and feelings are important to you. Moreover, good listening encourages partners "to open up and be willing to share," say Richard and Kristine Carlson, authors of Don't Sweat the Small Things in Love (Hyperion, 1999). The secret, say the Carlsons, is not just to "hear" what your partner is saying, but to be truly "present," having a heartfelt desire to understand what is being said and listening without being judgmental.

8. Maintain Your Sense of Self
Partners must learn to balance their needs as individuals with their needs as a couple. "On one hand, you don't want people to be too far apart emotionally. If you don't spend time together, you become disengaged emotionally," says Kaplan. "The other end of the spectrum is couples that become too dependent on each other and their individual identity gets lost." Ideally, the two of you should be close enough to have intimacy, yet "far enough away to have individual identity," says Kaplan. Don't be afraid to develop some friendships and interests separate from your partner.