Lewis had been seeing Emma Schofield for 18 months and had been excitedly planning their wedding.

But Lewis, 21, was unaware Emma had a sordid secret: For two weeks she had been having an affair— with his dad, Darren.

Six months after meeting Darren, Emma found herself falling for the 43-year-old builder and into his bed.

Emma, 27, from Blackburn, says she wrestled with choosing between her fiancé and her future father-in-law. She explains: “Standing beside Lewis at that barbecue in June 2011 was torture.

“I felt such a fraud knowing while I was on the arm of my fiancé it was his old man I had fallen for.

“I admitted the truth to Lewis five months ago.

“Even now I lie in bed and cry because it’s horrible what I did to him. But I found it impossible to control my feelings for his dad.”

Emma, who works in sales, fell for Lewis at a Christmas party in December 2009.

She says: “After a few dates I realised he was special.

“He treated me with respect, was the perfect gentleman and our sex life was fantastic.

“After two months he’d all but moved in and four months later he proposed saying, ‘I’ve never loved a girl as much as I love you and I want to make you happy for the rest of your life’. I said ‘yes’.”

Emma was yet to meet the labourer’s dad.

She says: “They hadn’t been close since his parents split around eight years earlier.

“I saw our engagement as a way of bringing them together.

“When we knocked on the door of his house, a few streets away, Darren answered and invited us in.

“He was charming and confident. I was instantly attracted to him, not in a sexual way, but I fell in love with his personality.

“We all became very close after that meeting and went out for drinks and to clubs together.

“Eight months ago Lewis and I were at Darren’s house after a night out. Darren and I were drunk but Lewis was sober — he was on call in case the alarm went off at his work, a builder’s yard a few miles away.

“We’d only been in five minutes when Lewis got a call-out.

“He phoned from work ten minutes later to say there had been a break-in and he wouldn’t behome for a few hours. I told him I would sleep in the spare room at his dad’s, as I didn’t fancy goinghome alone.

“I sat with Darren on the sofa with a glass of wine and he turned to me and said, ‘I don’t think I’ve ever seen you looking so attractive’.

“I was shocked, told him to stop it and pulled my short skirt down as it had accidentally ridden up. But he put his hand on my thigh.

“I turned to him and suddenly we kissed. Then I thought about Lewis and stopped him, saying, ‘This isn’t right, it isn’t fair on Lewis’. He said, ‘You’re right’.

“I decided the best thing to do was go to the spare room and go to sleep. As I lay under the covers. I thought, ‘What was I playing at?’ I loved Lewis, he was perfect for me.

“But underneath I knew I wanted Darren and not Lewis.

“Darren appeared and sat on the bed. He said, ‘I’m really sorry for what happened just now. Please don’t tell Lewis’.

“My emotions were all over the place, I pulled him towards me and we started kissing. Minutes later we were having sex.

“When it had finished Darren went back to his room and I lay on the bed in a state of shock. There was no going back now. But I felt so guilty and ashamed, ashamed that I’d betrayed Lewis, who was such a genuine person.

“For the next three months I saw Darren when Lewis wasn’t around, and tried to carry on as though nothing had happened.

“I was an emotional wreck. I’d gone from wanting to spend the rest of my life with Lewis to being unable to be intimate with him because I didn’t love him.

“I wanted to reset the clock and go back to how things were before all this happened — but I couldn’t.”

During all this, Lewis was planning the couple’s big day. Emma says: “He’d taken over planning the wedding because I was showing little interest. But I still couldn’t choose between them.

“I loved Darren and could see a future with him but Lewis deserved better than that, so I stuck it out.

“After three months of this charade I became so exhausted I told Darren we had to come clean.

“Darren and I met at his house and Lewis joined us. I took Lewis’s hand and said, ‘I’m sorry, but for the past few months I’ve been seeing your dad. I like you but I don’t love you. I love Darren’.

Lewis threw himself at Darren and they started fighting. Eventually Lewis marched to the front door and screamed, ‘I hope you two will be happy together, in hell!’

“The guilt and betrayal I felt towards him made me feel sick. I lost lots of weight, didn’t want to go out and sank into depression.

“But to drag things on with Lewis would have been more cruel.

“Darren and I plan to move in together. Darren’s hoping to patch things up with Lewis. Me and Lewis haven’t spoken since the fight, but I hope one day we can all be friends.”

Darren adds: “It’s a shame what’s happened and I didn’t want to hurt Lewis, but I’ve found Emma. Lewis will find someone else, he’s a good-looking lad. I hope one day we can be on good terms again.”

Lewis says: “It’s a nasty thing to do.

“I feel quite embarrassed about it. I don’t know if I’ll ever be friends with my dad again, well, definitely not while he’s with her.

“I’ve just got to get over it — and I am.”