If I asked you who your best friend is, many of you would point to your spouse or partner. Close friends share a strong emotional bond, enjoy spending time with each other and often have a lot in common. However, there are important elements of a romantic relationship that set it apart from a just-friends relationship--passion, sensuality, and physical attraction.

Unfortunately, in many long-term relationships, passion wanes as the years pass and the couple begins behaving more like close friends than romantic partners.

Sexual desire fluctuates throughout the life of a relationship

Every individual is different, which means that every couple is different. Take this one step further and it's clear that every couple has different levels of sexual desire. Despite the urge to compare ourselves to others as we search for the ideal "times per week," the fact is there is no magic number because a couple's sexuality is intensely personal and completely unique to the couple.

You're in very good company if the quantity and quality of sex fluctuates in your marriage or relationship. Many couples report steady declines as the years march on, others experience periods of little physical intimacy intermixed with sporadic increases in sex. Couples have different sexual rhythms.

Despite these natural fluctuations, there are mindsets that can creep into your relationship and negatively impact your attempts to keep passion alive. Be aware of them and you put yourself on the road toward a more fulfilling sex life with your partner.

The four mindsets that can destroy passion:

1. You believe that sex is separate from other parts of your relationship.

A relationship truism couples often forget: How you treat your partner outside the bedroom affects what happens inside the bedroom. If your partner perceives you as indifferent or judgmental, it shouldn't be a surprise when you hear "I'm really not in the mood tonight."

The seeds of passion are set outside the bedroom--nurture the emotional connection of your relationship and you'll nurture passion.

2. You're waiting for spontaneous sex to occur.

Please ignore the Hollywood movies that show couples knocking over every pot and pan in the kitchen (even pot and pans filled with ready-to-eat gourmet food) as they're overcome with desire and cannot wait to get to the bedroom to have sex. Spontaneous sexual combustion might have occurred when you and your partner were first dating, but for couples who survive past the two-year mark, life's spontaneous happenings are more likely to involve heartburn and indigestion than sex.

You need to plan for romantic moments, thereby creating them. Even if, over breakfast, you can't imagine yourself being in the mood later in the evening, if you set aside a time and create a romantic space, you might later surprise yourself when you become aroused.

Don't be passive about passion--successful couples work on creating passion.

3. You believe sex is mainly physical.

Sex is psychological, emotional and physical. For many, the road to great sex starts in their mind. You've probably heard the adage: "The most powerful sex organ is between the ears." Your imagination and fantasy life can be a great aphrodisiac. For this to occur, you and your partner need to openly communicate about your sexual desires and interests.

Feedback and discussions about what works and doesn't work in the bedroom will pave the way to a more fulfilling sex life.

4. You still believe in "the quickie."

Nothing kills passion like a hurried atmosphere. You're not a teenager any longer, translated: Your body and libido have slowed down a bit since raging sex hormones were the new kids on the block. Do you warm up before exercising? Do you let your car idle before heading off to work in the morning? You and your partner may have different warm-up times before feeling ready for sex--respect these differences and take it slow.

Give passion the time it deserves.

While you might not be able to recapture the sexual glory days of a new relationship, you (and your partner) can take the steps necessary to resuscitate romance and keep passion alive. Awareness of the above four mindsets is an important first step in reversing the toll the years often take on passionate relationships.

To discover other tips about how to build a more loving, passionate relationship, visit http://StrengthenYourRelationship.com/ and sign up for Dr. Nicastro's Relationship Toolbox Newsletter. As a bonus, you will receive the popular free reports, "The Four Mindsets that Can Topple Your Relationship" and "Relationship Self-defense: Control How You Argue Before Your Arguments Control You."

Author's Bio: 

Richard Nicastro, Ph.D. is a psychologist and relationship coach who is passionate about helping couples protect the sanctuary of their relationship. Rich is co-founder of LifeTalk Coaching, an internet-based coaching business that helps couples strengthen their relationships.