Reinvent date night
"If your date-night routine is boring and predictable, then date-night sex will likely be boring and predictable as well," says Dr Laura Berman, a US-based sex therapist and author of It's Not Him, It's You! (Dorling Kindersley, $45). Once a month, do something belly-flippingly scary. "When you engage in daring activities with your partner, such as riding a roller-coaster or bungee jumping, your brain releases dopamine and adrenaline, hormones that mimic the excitement you felt during your first months of dating." If adrenaline sports aren't your thing, rent a scary movie, says Dr Berman.
Get more sleep
You already know that a lack of shut-eye is bad for your health; now researchers are finding it's bad for relationships. Professors at the University of Pittsburgh studied 32 healthy, happily married couples with an average age of 32 and discovered that the wives' sleeplessness marred "positive marital interaction" the following day. However, when the husbands were sleep deprived, couples got along fine. "The key to a good night's sleep is routine. Just like a child needs to follow a pre-bedtime routine, so do we," explains Jo Lamble, psychologist and author of Answers To Everyday Questions About Relationships (Penguin, $19.95). Set an alarm for the same time each morning, even on weekends, she says, and you'll start crashing at a reasonable hour every night.
According to research published last year in the journal Personal Relationships, couples that are friends with other couples boast a happier relationship. Spending time with another couple normalises what's going on in your own life, says Lamble. "They argue over the same things. They lead as mundane an existence as you do – some of the time. And they like to spend time with you," she explains. "A couple without other couple friends can feel very isolated and this can put too much pressure on partners to be everything for each other."