Many people struggle with loss of desire in a long-term relationship. You WANT to want to have sex, but you don't really want to. Maybe you turn to the internet for help -- ideas to kickstart your stalled sex life. There are so many pages all too happy to give you advice or suggestions. What do you choose? I'm here to say that you don't have to worry too much about which technique you try -- they will ALL work! Let me explain. There was a study done once on the effectiveness of various treatments for warts (stick with me here!). They found that all the treatments were very similar in their effectiveness and that all the treatments were better than doing nothing at all. In other words, swinging a dead cat in a graveyard at midnight on the full moon will cure warts as well as Compound W, and both those things will cure them better than doing nothing. The conclusion? The placebo effect is a powerful thing.
Sexual desire is just like that. If your sex life is lacking in excitement or passion, or if desire has waned -- and face it: it is bound to in any long term relationship -- then just the intention to search for solution and try new things will have some effect, regardless of what the solution is. It's not just the placebo effect, though that's certainly a powerful part of it, too.
More than just the placebo effect, focusing your attention on what you want to change will cause some movement toward that change. Think of it like riding a bicycle. You aren't consciously thinking "I want to go right, so now I need to turn the handle bars right." You have the desire for going right, and your body makes it happen. If you decide you want more desire and seek out things that will help, your body will respond to that.
If you incorporate your partner into the project, all the better. Make an adventure of it. Together, seek out new ways to improve your sex life and try new things. Anything you discover together will have a positive effect, and the search just adds to the fun. Need some ideas for new things to look into? Here's a short list:
Shop for sex toys together, then use them!
Explore some herbal remedies - some people have great success with this
Watch porn together - explore the wide variety of ethically-produced porn
If you usually have sex with the lights on or off, switch it up
Set a timer and agree to stop when it goes off, even if you haven't climaxed
Listen to audio porn (for instance, the website Soundgasm)
Make a video
Take turns tying each other up
Try a 30 day masturbation challenge - no sex, but daily masturbation
Consider hormonal treatment for a jump start
If you usually fantasize during sex, try not fantasizing
Make a date to have sex
Invent a pre-sex ritual together
If you don't usually fantasize, try it!
Set a goal to have sex in every room of your house
Have a totally selfish session - all pleasure for just one person. The other only gives.
Watch a video about Orgasmic Meditation and try it
Try to make the other person climax while they read aloud from their favorite book
Find a place to have sex outside
Read erotica to each other
Go to a marriage counselor to talk about your sex life
Comparison shop for better lube
Explore more anal stimulation
Go to a sex club
Write a profile together on a swinger website, just for fun
Buy a remote controlled bullet, wear it on a night out
Go to a sex workshop
Commit to thinking about sex and being aware of your genitals at least 3x a day
Read a book on better sex together and compare notes
Get a boudoir photographer to take sexy pictures of you together
Commit to only having sex with your eyes open
Get the Kama Sutra and try each position
Buy a flogger and use it
Go to a rope typing course
Make out in the car
Do more Kegels, and think specifically about sex when you do them
Try to find someone for a threesome - just the looking is arousing
Have a threesome
Watch each other masturbate
And finally, put some sentimental items from your life together in a bag, take it out to a graveyard at midnight and one of you swing it over your head, while you both sing "your" song. That one's a sure bet!
All of these things involve 7 important steps that provide attention, and intention, to improving your sex life: 1) you think about it, 2) you suggest it to your partner, 3) you and your partner talk about it, 4) together you decide to try it, 5) you prepare to try it, 6) you try it, 7) you talk about what it was like. Regardless of whether the thing itself was subjectively good for you, all that attention and connection and communication with your partner is highly likely to positively effect your sex life and your level of desire.