One of the most significant challenges of a long-term relationship, like marriage, has got to be keeping the fires burning. Every couple that has been together for more than four years has, I'm sure, experienced some measure of the doldrums in their relationship.

Having moved way past that early stage of marriage where you're barely able to keep your hands off one other, of scarcely coming up for air, and of spooning together in bed way past 9:00 a.m. on Saturday mornings, most couples find themselves in a situation where sex is as mundane an activity as taking out the trash.

The sad thing is that this is not the way we imagined it. When most of us started our relationships, especially if we were young, we could not imagine losing that hot intensity we first felt. Yes, of course our intelligence told us that life might temper passion here and there, but we could not envision that there could be a virtual fallout in the areas of sexual desire or inventiveness.

Because sex gets the kind of attention that it does daily, we are never allowed to forget what sex should mean in a relationship. We know intuitively that we need to keep the sexual connection in our marriages alive if we hope to emerge with a relationship that will stand the test of time.

That being said, having the good intention of enjoying a love for a lifetime is not enough to make it happen. Like any other aspect of our lives where we hope to achieve and do consistently well, a marriage requires deliberate planning and insight in the area of preserving sexual chemistry. Nothing in life that is worth its salt comes about automatically. Sadly, the language of popular culture via songs, books and movies does not teach us this.

We have been seduced into a way of perceiving life which seems to suggest that passion and sexual chemistry are always instant and unsolicited. In the now famous scenario of "boy meets girl" and "girl falls helplessly in love," we have come to acquaint romantic relationships with afterthought more so than forethought. In other words, it can appear decidedly unromantic to plan romance.

In the cut and thrust of the very busy lives we now lead, this philosophy, however, cannot hold sway. The deliberate planning, which we are prone to apply to our careers, our academic advancement and even to our financial prosperity, is also needed to secure a successful marriage.

These 10 tips suggest some active ways that you may go about putting the sizzle back into your marriage:

1. Share your sexual expectations with one another and work on finding a common ground. After going so long without discussing this important topic, you’ll more than likely be more alike in your responses than you think.

2. Understand that even with expectations, our individual sexuality is not etched in stone: our individual sexual needs can and do change as we mature and we need to deal with our sexual/emotional baggage as we become exposed to new knowledge about sex. This means that each spouse must remain flexible and demonstrate a willingness to compromise to keep the other sexually fulfilled.

3. Be aware that hormonal differences between men and women can cause a mismatched sex-drive. This can be a test of love and patience and does keep the relationship interesting and unpredictable.

4. Have lots of sex, both spontaneous and planned. Research shows that the more a couple connects sexually, the more sex they want to experience with one another.

5. Do something different outside your normal sexual repertoire. This may involve having sex in the shower, in a safe outdoor environment like the backyard or garage (of course while observing decency laws), doing it in a different room of the house, switching up sexual positions, sharing a sexual fantasy or spending a night or weekend in a hotel room. This list is by no means exhaustive. Each one of you should is free to allow their imagination to take flight.

6. Preserve what I call "sexual tension" by deliberately agreeing to withhold sex for a couple of days or a even a week (actually the longer a couple withholds, the better the outcome). During this time, be free to touch and tease without going all or even half the way. Plan your night for full sexual exploration and explosion, and I guarantee you just might wake up the neighbors.

7. Maintain a regular date-night. Take the effort and dress to impress by doing formal dinners, but also mix up the dates with fun let-down-your-hair activities like going to a game or a night at the movies.

8. Practice regular sexual affirmation by telling one another when you’ve done a great job in bed—or where ever the act takes place.

9. Practice open and honest sharing when unhappy or dissatisfied in any aspect of the relationship, including the sex. Keeping your relationship free of clutter is critical to preserving intimacy and passion.

10. As a couple, try having an orgasm or two with your eyes wide open. It’s an act of deliberate vulnerability or self-exposure that will take your emotional and sexual intimacy to a new level.

"Denise J Charles" is an educator, counselor, relationship-coach, published author and blogger. She holds a Masters Degree in Education and is a qualified trainer-of-trainers. Denise is Executive Director of "Better Blends Relationship Institute", a counseling and training entity founded by herself and her husband Gabriel. Denise’s blog on sex can be found "here". Denise’s soon to be released new book is "How To Have Mind-Blowing Sex Without Losing Your Brain".