Supermodel Cindy Crawford, 51, once revealed that she and husband Rande Gerber, 55, often sneak off to their beachside guesthouse for some, shall we say, alone time. "Sometimes you just have to do it!" she said.
And they're not the only 50-somethings enjoying a healthy love life, reports the Telegraph.
A recent study of 8,000 adults from Trinity College Dublin found that 59 per cent of over-50s are having regular sex, with a third of those having it once or twice a week, if not more.
"I often find clients" sex lives improve vastly in their 40s and 50s,' says Barbara Bloomfield, a Relate therapist and author of Couples Therapy: Dramas of Love and Sex.
"Firstly, ask any 30-something parent and they'll tell you that having young children is the biggest passion-killer of all. In midlife, however, your children may well be teenagers or older, so they need you less and go out more.
A lot of people report an improvement in their sex lives when their children leave home; it's a time when marriages get the va-va-voom back.'
Another factor is that divorce rates among the over-50s are rising, says Bloomfield. "One of the reasons older women are having a lot of good sex is because they're in a new relationship, especially if they've been unhappy in their previous one," she adds.
"Lastly, women often come into their own at this age. They are confident and have fewer hang-ups. They are much more aware of their bodies and what they like and don't like - and they're not afraid to tell their partner."
But now for the bad news: sex over 50 can be problematical. Hormonal changes that take place during the perimenopause (typically from your mid-40s) can impact on libido.
Declining oestrogen levels can cause vaginal dryness and a thinning of the vaginal wall, which can make sex uncomfortable. "This is called vaginal atrophy and it can be dreadful," says Bloomfield. "I tell my clients to ask their GP for a vitamin E cream."
Testosterone levels (important for a woman's arousal) also begin to decline, which can cause tiredness and irritability. Men can be affected by their own 'man-opause', too.
Their levels of testosterone start to drop by about one per cent every year from the age of 30-40, which can cause reduced libido, erectile problems, tiredness and poor sleep.
But there are plenty of things you can do to boost the libido - and the benefits of a regular sex life are numerous.
According to the Trinity study, couples who continued to have sex were more positive about ageing, enjoyed better health with fewer long-term conditions, and were less prone to depression.
Midlife sex can also improve heart health, lower blood pressure and release the feel-good hormones endorphins, which act as a natural painkiller.
A study by Dr David Weeks, former head of old-age psychology at the Royal Edinburgh Hospital, found that middle-aged people who have regular sex look on average five to seven years younger than those who rarely have sex.
"There are countless reasons to maintain your sex life," says Barbara Bloomfield. "Yet often, one half of a couple decides to give up sex, which is when resentment or boredom can creep in." So what can you do?
Part of the problem is that middle-aged women increasingly have what's called "reactive arousal", whereas men have "primary arousal".
"That means a man will just have to look at something he finds attractive and he'll feel aroused," explains Bloomfield.
"Reactive arousal means women get aroused by being cuddled and kissed. Long kisses - around 15 seconds - are effective. I've tried this technique with quite a few of my couples through Relate. It's very simple but it works.
"When I see unhappy couples, I often find the thing they adored about their partner when they met has gradually become the thing they can't stand about them," continues Bloomfield.
"The ambitious, driven partner who looked terribly attractive when you were 23 becomes the partner who is accused of being a workaholic. The life and soul of the party is fun at first, but becomes tiresome when you have responsibilities.
I tell clients that people only change a little over time and how their partner was when they met them is how they shall remain."
However Janice Hiller, a consultant clinical psychologist at the Tavistock Centre for Couple Relationships, says she is seeing more empowered women in midlife than ever before at her practice - in other words, women who are questioning whether they're getting everything they want out of life.
"They are less willing to allow themselves to feel disregarded, undermined, neglected or ignored by their partners," she says. "I believe it's these women pushing up the divorce rates in mid-life and contributing to the studies about over-50s having great sex.
However, as a relationship psychologist I appreciate I only see the couples who are unhappy. The happy ones don't come to me, but I know many who are content and having great sex with their long-term partners.
These couples know how to arouse each other and they know that intimacy and good communication are vitally linked. And, crucially, the stresses of child-rearing have passed so they're less tired."
Sleep, it seems, is a prerequisite for good sex.
A report from the US recently published in the health journal Menopause studied more than 93,000 women aged 50-79 and found that short sleep duration (fewer than five hours a night) was associated with less satisfying sex lives.
"When you're tired, sex drive is usually the first thing to go," says nutritionist Marilyn Glenville, author of The Natural Health Bible for Women.
She recommends topping up your levels of magnesium, known as "nature's tranquilliser" thanks to its muscle- and nerve-calming properties, which promotes better sleep. Foods rich in magnesium include fish, green leafy vegetables and pumpkin and sunflower seeds.
Glenville also suggests improving your overall health. "If you don't feel healthy, it's harder to feel energetic and sexy," she explains. She advises following a balanced diet full of good fats like oily fish, eggs, nuts and seeds.
"Good fats are important for overcoming a low libido because sex hormones like testosterone are manufactured from the cholesterol contained within those foods." Foods rich in zinc - like spinach, beef and kidney beans - are also important for the production of sex hormones.
Lastly, Glenville says that getting regular exercise and managing stress can boost libido and mean you're in the mood for sex more regularly.
Which brings us on to our final, and perhaps most intriguing, question: how much sex should we be having?
"There's no such thing as a normal amount," says Bloomfield. "I've had 70-year-old clients who have said to me, 'Our sex life has gone off the boil a bit lately.'
And when I ask them how often they're having it they'll say, 'Only three times a week these days.' I also see young, attractive 20-something couples without children who are having sex every six months or not at all.
But on average I'd say once you're in your 40s and 50s, once a week to once a month is within the 'normal' range."
The key to good sex in later life, according to Bloomfield, is this: "When it comes to sex, don't get old before your time. Push yourself a little bit. That's not to say you should do things you don't want to do, but keep trying new things and don't fall into the trap of just not making the effort.
"Sex in later life is like the gym - you know the benefits but often you just can't be bothered to go and there's something good on TV you'd rather watch. But when you do it, you remember how much you enjoy it and how good you feel afterwards."
After all, she adds, "Sex is like a muscle - use it or lose it."