Mrs Lamb, 41, lost more than 3st in weight to make sure that she would be healthy enough for the transplant operation in October 2009.
The couple were even filmed for a BBC show which documented the story of her gift of love. But they did not live happily ever after.
Just a few years after the life-saving procedure, their marriage was over when Mr Lamb walked out on his wife in August 2012.
Mrs Lamb is adamant that her husband started having an affair with her friend – a claim he categorically denies.
He moved his belongings out of their marital home one evening while she was working a night shift at Tesco.
He also took the TV and stereo before posting the keys through the letterbox without a note or letter, she claims.
The couple, from Ivybridge, Devon, met when they were both drivers for a private ambulance firm and started dating in 2004.
After a brief split, when they had to live apart from each other for a short period of time, they decided to get married in 2007.
However, Mr Lamb’s condition meant he soon became dependent on gruelling dialysis sessions.
His wife explained: ‘He needed a new kidney or he would die. He was on dialysis three times a week. I told Andy he should go through with it [the transplant].
‘He had children from an earlier relationship and he wanted to be there for them.’ Mrs Lamb says she now regrets donating the kidney to her husband and wishes she could have it back – if only to donate it to someone more deserving.
She told the Sunday People: ‘I would definitely go through the operation again but I wouldn’t give the kidney to him.
‘I hate him. If I could, then I would take it back and give it to someone else.
‘Obviously I don’t want people to be put off putting their names on the organ donor list.
‘But all I want from him is his name on the divorce papers.’
Mr Lamb, 45, who denies having an affair with his wife’s friend, said: ‘I never wanted her to donate her kidney because it was a big risk. But she insisted and I’ll always owe her my life.’
He added: ‘I loved her but our relationship wasn’t working. We had big rows and her family never liked me.
‘Despite what Samantha believes, I have never been with her friend. I just helped her to train her dog.’
The mother-of-one now wants a divorce and says that she is trying to get on with her life – although she is reminded about the break-up whenever she sees her 4in operation scar.
She does have one comfort, however, saying: ‘At least he always has to remember where his kidney came from.’