Hot-tub double killer cheated on me with daughter's best pal; Mother-of-two hits out.
HOT-TUB killer Shaun Alexander's lover told yesterday how he two-timed her with her daughter's friend.
And Kathleen Kerr said the crazed former soldier spoke openly of his plans to kill estranged wife Nicola.
Alexander, 32, carried out his threat just weeks after Kathleen, 34, ended their relationship - and days after she discovered he had cheated on her with 16-year-old Adele Kettrick.
Adele revealed last week that she started seeing Alexander in August, before mum-of-two Kathleen broke up with him.
Kathleen claimed yesterday that Alexander mentally abused her and stole pounds 4000 from her credit cards to spend on other women.
He was known in his home area in Fife as a womaniser but she only realised how bad he was after they started dating.
She said: 'He told me one night he was going to kill Nicki. At the time, I thought it was just an idle threat.
'I wish I'd done something about it now.Who knows? I may have been able to stop the murders. Initially, he was as nice as pie and could charm anyone with his banter.
'But there were times when the mask slipped and you saw the real Shaun.
'He would try to fight anyone who looked at him the wrong way and would scream and shout at me if I did the slightest thing wrong.
'At times he scared the hell out me. 'And it didn't matter if they were 16 or 36, if a woman caught his eye he'd have them.'
Kathleen's daughter Stacey told her Alexander had been cheating on her with Adele days before he butchered Nicola and her new boyfriend Kevin Braid, 42, with a knife and crowbar.
He burst into businessman Kevin's garden in Leslie, Fife, as the pair relaxed in the hot tub with another couple.
Kathleen said yesterday: 'It came as a bit of a shock that he was going with a very young girl behind my back.
'The fact it was one of my daughter's best pals made it worse. But his two-timing is absolutely nothing when you compare it to what he went on to do to Nicki and Kevin.
'I've since met Adele and we hugged each other and talked for a while. She was a young girl who was completely used by this beast.'
Kathleen, from Glenrothes, also revealed that despite his horrific crime, Alexander, who has at least five kids by different women, says he wants to be 'a good dad' to Taylor, his 18-month-old son with student nurse Nicola.
He wrote to her from Perth Prison before his conviction, asking her to give the little boy his wedding ring, which he had left with her.
He wrote: 'He hasn't got anything of me and I don't know when I will see him again. I hope I can be a good dad for him later on as it may be a while before I see him again.'
But Kathleen said she did not want to distress 23-year-old Nicola's parents, Richard and Brenda, who are Taylor's guardians.
She added: 'I'll hand the ring over to the police and let them deal with it.'
CHEATED: Kathleen Kerr, pictured with her 16-year-old daughter Stacey, had a four-month relationship with hot-tub killer Shaun Alexander, top right, but he was seeing Adele Kettrick, above right, at the same time. Left, Alexander's ring