It’s funny how sex factors into the way people describe the state of their relationships. Studies show that, when things are going well, sex contributes only 15 percent to the overall satisfaction of a relationship. But if things aren’t going well, it contributes 85 percent to the overall dissatisfaction.

Sex has many advantages to both people involved. Here are just a few.

1. Because you said so

Even though you may not have promised to “love, honor, and have sex once a week” when you made a commitment to your relationship, it was understood that sex would be part of that bargain.

Imagine how the marriage rates would go down if people said, “I’ll marry you, but don’t expect sex.” If you polled one thousand people on the street and asked them, “Is it reasonable to expect to have to have sex when you are married?” the overwhelming majority would say yes. If you expect a monogamous commitment from your partner, then it stands to reason that you will be a cooperative sex partner.

2. Sex helps you forget

Oxytocin, which triggers orgasm, has an amnesic effect that lasts up to five hours. So for a period of time you forget that he maxed out your Visa card or she was an hour late getting home from work. Women get an additional benefit. During orgasm that parts of the brain that govern fear, anxiety, and stress are switched off. (Faking orgasm gives no such benefit.)

3. Sex rewires you for pleasure

Every time you share a positive experience with your partner, your brain comes to associate him or her with pleasure. You can transform any relationship simply by increasing the number of enjoyable times you share together.

4. Sex puts the “P” back in partnership

Passion is what separates your relationship with your intimate partner from those with girlfriends and buddies. Yes, you two are best friends and confidants, but without sex you will not have passion.

The following are from a 1997 study in the British Medical Journal-

5. Heightened sense of smell

After sex, production of prolactin surges, causing stem cells in the brain to develop new neurons in the brain’s smell center (olfactory bulb).

6. Weight loss

Rambunctious sex burns a minimum of two hundred calories, about the same as running fifteen minutes on a treadmill. British researchers determined that the equivalent of six Big Macs can be worked off by having sex three times a week for a year.

7. Reduced depression

Prostaglandin, a hormone found in semen, modulates female hormones. Orgasm releases endorphins, producing a sense of well-being and euphoria.

8. Pain relief

During sex, levels of oxytocin surge five times their normal level, releasing endorphins that alleviate pain. Sex also prompts production of estrogen, which reduces the pain of PMS.

9. Healthier heart

Women who have more sex have higher levels of estrogen, which protects against heart disease.

10. Cure for the common cold

Once-a-week sex produces 30 percent higher levels of immunoglobulin A, which boosts the immune system.

11. Better bladder control

Sex strengthens the pelvic muscles that control the flow of urine.

12. Peppy prostate

Some urologists believe they see a relationship between infrequency of ejaculation in men and cancer in the prostate. In this case solo sex works just as well, but why out on all the other benefits?

13. Shiny hair, glowing skin

For women, extra estrogen from orgasm makes hair shine. Sweat produced during sex cleanses the pores and makes skin glow. Serotonin produces the after glow of sex.

14. Calming effect

Sex is ten times more effective than Valium, with no side effects.

15. Relief for a stuffy nose

Really. Sex is a natural antihistamine. It can even help combat hay fever and asthma.

16. Firmer tummy and butt

Regular sex can firm your tummy and butt, plus improve posture.

17. Boosts immune system

Endorphins stimulate immune-system cells that fight disease.

18. Forever young

Sex actually slows down the aging process. It lowers cortisol levels in the bloodstream, which reduces stress and slows down the aging process.

19. Protection against Alzheimer’s and osteoporosis

Women who have more sex have higher levels of estrogen, which protects against Alzheimer’s and osteoporosis.

20. Euphoria

Who wouldn’t want more? The best way to get a natural high is sex!