Sonia Todkill, 28, an educational writer and teacher, and green-keeper Robert Green, 30, have been together for 10 years. They were married in Fiji on New Years's Eve 2008, just after completing the challenge.

The challenge: To have sex every day, as writer Charla Miller did in her book 365 Nights ($24.95, Murdoch Books).

She says: "We've always had fantastic sexual chemistry, but while we used to have sex up to three or four times a day when we first met, that's dropped to about three times a week. This challenge should add some spice to our sex life."

He says: "Bring it on!"

Week 1: "We woke up on the first morning of the challenge feeling full of anticipation. That evening, when Robbie went to bed early (as he gets up at 3.30am for work), I followed him, which I wouldn't normally do. I also dressed up in his favourite lingerie, a sexy aqua set. We were both looking forward to it and the sex was sensational. But I'm not the only one making more effort; throughout the week, Robbie's been very romantic and one night he even lit candles and placed them around the bath. This, I stress, is not standard practice, and it will be very interesting to see if we can keep it up for 30 days."

Week 2: "Early in the week, I decide to surprise Robbie by meeting him at home at lunchtime for a midday sex session. I'd been waiting for an hour in skimpy lingerie, only for him to call after an hour to say he was going grocery shopping! That night we had half-hearted sex to make up for it. But by the end of the week the novelty of daily sex had started to wear off and neither of us were making an effort. It's not much fun when it's contrived, and at times having sex almost felt like a duty. Shopping. Check. Washing up. Check. Laundry. Check. Sex. Check!"

Week 3: "To ensure our daily sessions don't get too predictable, we've started experimenting with different positions. Usually, we just stick to missionary or me on top, but this week we've had lots more oral sex and even 69ers, which Robbie loved, but I was ambivalent about. I thought that after three weeks of daily sex, we'd feel closer to each other, but I haven't felt a huge shift in our intimacy. But I'm noticeably more relaxed, and I feel as though we're having more fun with each other - both in and out of the bedroom."

Week 4: "Having sex at the same time every time - hello, 9pm - was beginning to get a little boring, so we put some porn on one afternoon to liven things up. Sadly, the DVD stuck after about five minutes on a very, um, interesting image... which kind of killed the moment! However, I was still aroused the next morning so I initiated sex, much to Robbie's delight, and it was slow, intimate and sexy. Another memorable session kicked off after a night at the pub when we had sex in the kitchen. It's something he's wanted to do for a while so we can tick that one off the list now too! But I think we forgot the close the blinds in the lounge. Our elderly neighbour acted very strangely and seemed to be having trouble looking us in the eye when we all went to collect our newspapers on Sunday morning!"

She says: "Occasionally, we've struggled to feel motivated to have sex every day but once we start, it's usually great. Plus, doing it everyday has meant Robbie doesn't have to harass me for sex (as he sometimes does) because he knows he's definitely getting it! I also feel as though we're more in sync; we're going to bed at the same time more often and even showering and bathing together more.

He says: "The atmosphere, music and candles have really spiced things up, and I feel as though Sonia's been making more of an effort by wearing sexy lingerie, and shaving her legs more often. She's been very adventurous too, wanting to try new positions and locations, which is great. But ultimately, having sex more often doesn't make me love her any more - we have a great relationship, and after 11 years, there's more to it than just sex."

For more road-tested relationship improvers, read this month's marie claire.