Ten signs your wife is having an affair.

CAROL Mason is the author of new novel The Secrets Of Married Women, a tale of boredom and betrayal that's being billed as grown-up chick lit. Here the writer, originally from Newcastle, reveals the 10 tell-tale signs that your wife might be playing away...

ONE: She gives you the Christmas present you want, and some you never knew you wanted: a one-year gym membership; a gift certificate for a back wax; a box of L'Oreal Excellence 100 per cent grey coverage. Or, worse, last year she gave you the membership, the wax and the dye, and this year she's bought you a lawn mower with a more powerful motor.

Moral: If she's hinting you've let yourself go, act immediately to become your best self before she finds somebody else and doesn't care what you look like any more.

TWO: She never nags or picks a fight any more, in fact, she's actually nice to you. She doesn't sit there and bore you about her friends, her day, her problems, the dog, a jam jar. She doesn't keep dragging you out shopping, or to a friend's house on a weekend, when all you want to do is sit and watch the match. In fact, you can now watch anything you want on the box. She's not bothered about what you do any more, or about your day, or, really, about anything to do with your life.

Moral: If she's extra nice to you she's overcompensating for her guilty behaviour. If she's lost interest in you, she's interested in somebody else.

THREE: She's behaving differently in the bedroom. This can go one of several ways: she's constantly trying to convince you that you have a headache, and when you insist you haven't, she takes three-hour baths and only comes out when she knows you're fast asleep; your sex life seems normal... except for those orgasms she used to have absolutely every time, which don't happen any more; she's suddenly got a PhD in Positions and you've no idea how she got so creative; she insists on lights off, and she sometimes calls you by a new pet name - Andy, or Keith or somebody. It's cute. You'll have to remember to come up with an equally endearing new one for her.

Moral: If she's gone off sex, it's probably just sex with you. If she has stopped being satisfied, she's given up pretending your sex life is fantastic, because she's having the real fantastic elsewhere. And, if you're not teaching an old dog new tricks, somebody else obviously is.

FOUR: She no longer asks you if her bum looks big in this, or that. She used to be so self-critical, but now she seems to love her body. She lives at the gym. She's buying hordes of new clothes. And she won't go to work unless she looks fabulous and she's brushed her tongue three times. Not to mention the new underwear... the gold and black lacy thong you found under the bed, the one that made you wonder if your neighbour got drunk and stumbled into the wrong house.

Moral: If she's spent years having no self-esteem while she's been married to you, and now she suddenly loves herself, maybe somebody else is loving her too.

FIVE: She's never home. She'll pop out for a pint of milk and come back on Tuesday. You're getting really worried about the dog; his walks around the block are taking five hours, and shouldn't she be a millionaire by now with all this overtime she's working? If you ever ask her where she goes, first she gets defensive, then she gives an explanation that goes on for 10 years, with more detail than you've been genetically programmed to cope with.

Moral: When she talks, listen. You just might catch her telling a lie. Or, by listening better in the first place, give her less of a reason to cheat.

SIX: She's conjoined to her mobile phone. She takes it to bed with her, straps it on in the shower and checks for messages every 30 seconds. Yet whenever you try to phone her, it's always switched off. And you have no idea who rings her any more, because now she deletes all her messages as they come in. Ditto emails.

Moral: If she always hangs up when you walk in the room, grab a clue! Come on, this one really isn't rocket science!

SEVEN: She smells differently. It's... hang on... men's cologne! When you ask her about it, she says she was in Debenham's trying out a new one for you. When this happens three times a week for six months, you have to wonder: does she have a cologne-trying sickness? And is there a pill she can take for it?

Moral: If she smells of cologne and it's not yours, she's been snogging somebody else. Either that, or their clothes have been having an affair while their bodies weren't present. Believe what you will.

EIGHT: Her friends suddenly act funny around you. Either they avoid meeting your eye, or they look at you like you're Dr Crippen, or, even worse, they seem to feel a bit sorry for you.

Moral: If she's cheating, her best friends will know. They'll think you're either a mug, or just a really bad husband.

NINE: She's making you into a new you - encouraging you to experiment with new food, to dress differently, to like a different type of music, to want to see a film that would never have been your thing previously.

Moral: It's a woman's idea of human cloning. She's making you more like him, to make being with you a shade more bearable, until she can be with him again. Something you didn't know: Judy Garland was thinking of you when she said: "Always be a first-rate version of yourself instead of a second-rate version of somebody else."

TEN: She starts asking philosophical questions that get progressively more personal and practical. Like: "Do you think it's possible to love more than one person at the same time?"; "Don't you ever miss being free to be with somebody else?"; "Just supposing we were to split up, who gets custody of the dog?".

Moral: If she sounds like she might want to leave you, she does. All she's waiting for is the opportunity.