LIPSTICK on his collar is now old hat when it comes to spotting a clue that your man is having an affair — instead, keep an eye on his music downloads.

Former mistress Clare Oke-Smith reckons a sudden change in favourite bands is one of the textbook new red flags.

6 Duped...Clare Oke-Smith started the romance after she was told her lover's marriage was over Credit: Array

And she has a special reason for wanting Sun readers to know exactly what to look out for.

She still suffers terrible shame for letting herself be “duped” into an affair with a married father-of-two because of the hurt she caused his unsuspecting wife.

So the 29-year-old is now sharing all the ways she noticed her lover was behaving while trying to woo her and cover up his affair to his wife.

Clare fell for the handsome love rat after he convinced her that his marriage was over.

She said: “I never thought that I would become a mistress — I hate the idea of taking another woman’s husband.

“I was effectively conned into becoming the lover of a married man.

“I believe men cheat because they reach a stage where they wonder if that is all there is and want to test their manhood.

6 Insight...The former mistress believes men cheat to test their manhood Credit: Array

THE TEN SIGNS HE IS STRAYING 1. LATE NIGHTS A big pointer is if your partner is staying up well after you have gone to bed. It’s easy to FaceTime or Skype a lover in the early hours, while the family is safely asleep in bed. 2. MYSTERY SPENDING If your other half has taken out a new credit card without mentioning it to you, this is a red flag. Look out for the bills arriving which are immediately spirited away. Or if you see new plastic appear in his wallet keep your wits about you – it may have an online statement you can’t see. Likewise, another big clue is mysterious big-money purchases appearing on bank statements. If he wasn’t with you splashing the cash, the question is: who was he with? 3. CHANGING TASTES If your beau is suddenly interested in new music and downloading tunes from bands he had never heard of before, be alert. This influence may be coming from someone whose opinion he values, and who he is desperate to impress. 4. TECH SECRECY If your other half hides their phone or laptop from you, or locks it with a new code this may be cause for concern. 5. SARCASM I learned from overhearing calls that when a person is lying they have very little time to make up a story. Sarcasm is one way to bluster through explanations. Wise-crack answers may mean you are being lied to. 6. MORE TIME BEING SPENT WITH FEMALE CO-WORKER Spending more time than usual with a woman from work, chatting to her online or arranging work trips in which she is always a part, is a red flag. This is how my lover covered up many of his liaisons with me. 7. NEW MANNERISMS Using new phrases, trendy slang or mannerisms is a big clue. If they’re spending time with a younger woman they’ll subconsciously pick up many on-trend expressions they never used before. 8. BECOMING A PEACOCK Taking more pride in their appearance, buying new clothes, dieting or becoming very keen on visiting the gym is a classic sign of philandering. They thought they were good enough for you before, so why are they having doubts now? Could there be someone want to impress? 9. SEX LIFE LOSING ITS SPARKLE Most men, no matter how duplicitous, find it hard to sleep with two women at the same time. It takes an awful lot of energy and planning so your love life will suffer if you are living with a cheat. 10. EMOTIONAL DISTANCE If his eye is wandering your partner may stop letting you in on their plans, or being evasive about things like booking holidays or days out.

“It’s a cliche, but it’s often part of a mid-life crisis — they think they will regain their youth by bedding a younger woman.

“I think married men often search for women who seem vulnerable, because this makes them more susceptible to their charm.

“Often they are going through a period of stress or even depression, and feel they need to bring excitement into their life.”

He spent £3,000 on me on just one night out

She continued: “I have made a promise to myself, I will never be a mistress again, as my relationship with a married man ended very badly and left me both depressed and ill, with my self-confidence shattered.

“I’m just glad I can help other women spot the warning signs.”

The online PA, who lives in New Cross, South East London, first met Jeremy (not his real name) when he hired her to work for him.

Clare said: “We met in October 2013.

“He contacted me over email to say he wanted to hire me as an online PA for a music management business.

“There was a picture of me on my agency profile and I now suspect that was what attracted him.

“At the time I was lonely and vulnerable, having just come out of a relationship.

“He was 35, very confident and seemed successful.

“He sent me work but we became more chatty.

“After a couple of months he suggested we meet, and said he would come and see me in Newcastle where I was living at the time from his home in North London.

6 Sworn off...The affair made Clare depressed and ill Credit: Array

“I was shocked to hear he was married, with two young children who were three and five at the time, as he was so flirtatious.

“But he said he was in the process of separating.

“He and his wife didn’t have sex.

“I believed him — I was really falling for him.

“When he arrived at my home he was chatty, flattering, bearing gifts and whisked me out for an expensive meal.

“We slept together almost straight away.

“He stayed with me for almost two weeks — I later found out he’d told his wife he was on a business trip.

“He bought me presents such as beautiful shoes and a handbag, using a credit card I found out he’d taken out after he hired me.

“He spent £3,000 on me in one night when we went to an expensive lap-dancing club which I hated.

“But I was being swept off my feet, and I fell in love with him.

6 Over...The affair ended after a year when Clare received an angry call from his wife Credit: Collect

6 The love rat was married with two young children during the affair

“I began to suspect he was not actually in the process of getting separated when he forbade me from calling him on his mobile.

“We only talked via Skype late at night.

“I began to realise I was now in the role of ‘mistress’ but persuaded myself I wasn’t hurting anyone, as she didn’t know about me.

“I thought mistresses were women who sat about filing their nails, not go-ahead intelligent women like me.

“I’d never thought of myself as a mistress but there I was, effectively a kept woman.

“We talked to each other for several hours three or four nights a week, always in the early hours of the morning.

“He came up to see me often, faking business trips.

“We started to make plans for him leaving his wife and moving in with me.

“I lived for his visits and our talks late into the night.”

I realised I was only there for one thing – sex

But Clare’s affair came crashing down a year after it began.

She recalled: “I got a phone call from his wife.

“She asked if I was Clare — I knew who it was straight away.

“She shouted, ‘Stay away from my husband,’ and ranted about me being a home-wrecker until I ended the call shaking and crying.

“I felt as if a disaster was looming, but still I didn’t leave him.

“As the weeks went on and he didn’t leave her I realised the truth, I was only there for one thing — sex.

“He didn’t care about me, he just wanted a fling.

“I’d been an idiot.

“I was ill, exhausted by the situation and the lies, and after one terrible row he left me high and dry.

6 Lesson learned...Clare wants to help other women spot the warning signs Credit: Array

“Emotionally he had taken everything and given me nothing.”

Clare vowed: “I’ll never be the ‘other woman’ again.

“You’d have to have a heart of stone to cope with the despair, the false promises and lies.

“You’re just a prize to them, a symbol of their mid-life crisis like a fast car.

“It put me off men and dating for over a year, and I am only just dipping my toe in the water again — and isn’t going to be with a married man.

“As someone that knows, I have a list of tips so women in relationships can look at to see if their man is cheating.

MOST READ IN FABULOUS NOT ROCKET SCIENCE Mum mocked for ‘hack’ to work out what anything costs in Poundland SOAP & GLORY The glam soap stars who look a world away from their alter egos PEG PRICE Mum asks how much the Tooth Fairy gives kids & gets some ‘obscene’ amounts COSY COLLECTION Sainsbury's launches cosy line of loungewear & dresses priced from £3.50 GOOD AS NEW Mum gets son’s grubby white T-shirt sparkling again with FREE cleaning hack FAMILY MATTERS One of UK’s first gay dads, 50, welcomes baby with daughter’s ex 25

“At least helping others spot a philanderer means something positive came out of the mess.”

In other relationship news, these women have revealed that their partners have never seen them without makeup, until now.

Plus almost a third of couples are trapped in a sexless marriage just like Ulrika Jonsson, research finds.

And this wife has shared her husband's cringeworthy spreadsheet detailing the 27 attempts he's made to intiate sex and all of her "excuses."