Anyone who has run a marathon knows about commitment. To compete, the athlete relies on extensive training and physical fitness. But when the initial enthusiasm wanes and the painful, long-distance realities grip the runner's body, it is sheer dedication -- commitment to completing what she started -- that sustains the runner's motivation as she reaches for the finish line.

A relationship is a lot like running a marathon. There are highs and lows, challenges and rewards, and times when you may want to give up -- when it feels too difficult to continue. What will keep you on track and moving forward when your relationship hits the inevitable rough patch? Will love be enough?

Commitment: Your relationship lifeline

Commitment is a belief in relationship permanence and the understanding that at times your union will need a life-jacket to stay afloat.

When you and your partner are committed to the relationship, the union remains more important then your (and your partner's) individual needs. Without mutual commitment, deep trust will never take root and intimacy will wither. When one person's commitment is tenuous, the very fabric of the relationship is weakened. A lack of commitment reduces the buffer that holds relationships together during times of conflict and stress. Imagine living with the fear that periodic slumps in your relationship can cause your partner to bail.

Trust and deep intimacy will only grow in the soil of commitment.

Commitment has a dual role in your relationship. You can view commitment as the vehicle to help deepen your love, and you can also view it as a safety net of sorts, a way to protect your marriage or relationship during the difficult periods that each and every relationship experiences.

Commitment allows love and intimacy to mature over time. Someone who ends a relationship because the excitement of new love has diminished misses out on the opportunities that relationships bring for individual and mutual growth.

Some erroneously believe that a commitment like "till death do us part" means foolishly locking yourself into a lifetime of potential unhappiness. No one should commit to a relationship that cannot meet their needs. Your needs (and your partner's needs) do matter and should be part of the overall commitment equation. But life and relationships are complicated, and there will be stretches of time when your partner does not meet your needs (and you will not meet your partner's needs). Commitment is what will get you through those rough stretches, enabling each of you to get back on track in meeting each other's needs once again.

All couples (married and unmarried) face an enormous challenge: How to stay devoted to one another throughout the life of your relationship, even when early enthusiasm and euphoria naturally wane.

Commitment is a very personal process. Unfortunately, for some it will mean blind dedication to a union that rarely meets their needs, while others eschew commitment and impulsively use the ebb and flow of happiness as the gauge whether to stay or leave. Both of these approaches are flawed. Ideally, commitment will remain in place as happiness comes and goes and your relationship finds its footing along life's shifting terrain.

Commitment checklist:

Commit to ________:

, understanding that love grows and deepens over a lifetime.

, acknowledging that all relationships go through ups and downs.

, continuously working toward a meaningful relationship that will transcend momentary happiness.

, working through problems with your partner (while resisting the temptation to get your needs met outside of the relationship).

, finding solutions that will keep your relationship moving forward.

, compromising (even when you think you're right).

, yourself and the relationship.

Don't commit to ________:

, anything that feels abusive.

, always sacrificing what's most important to you.

, the idea that if your relationship requires hard work it means your relationship is flawed.

, the mindset that it's acceptable for your needs to continuously go unmet.

One of the greatest challenges to commitment lies in the instant-gratification mindset -- the idea that you deserve to have what you want when you want it. The settings to our pleasure barometer have been altered, and humans are less willing to deal with frustrating circumstances or anything that feels like it stands in the way of immediate happiness. This poses a problem for relationships.

When you make decisions about your relationship based solely on the need to feel happy (all the time), you abandon commitment and the rich opportunities that are essential for your relationship to grow.

I invite you to think about what commitment means to you. What you are committing to in your marriage or relationship?