Scott Blackwood, 30, was battered, stabbed, stamped on, strangled and tied to a bath before an attempt was made to set him on fire.
Georgina Smith, 22, unleashed the violence on Scott, along with co-accused Allan Nicol, 36, and Thomas Moore, 26, despite claiming that she loved him.
She was found guilty of culpable homicide. Nicol and Moore were convicted of murdering Scott at Wheatley Road, Saltcoats, on July 3 or 4, 2013. Last month they were jailed for life and ordered to serve at least 20 years each.
Yesterday Judge Lord McEwan told Smith: "You have been found guilty by the jury of the culpable homicide of Scott Blackwood, a litany of horrific assaults on this young man.
"In your evidence you said you loved him, well, each man kills the thing he loves and that is what you have done."
Lord McEwan said that three victim impact statements from Scott's family revealed the consequences for them of his death are "dire to put it mildly".
Smith showed no emotion as she was led away to begin her sentence.
Scott was relentlessly bullied before he was set upon. He suffered 72 injuries, including scalds and chemical burns. He also suffered 13 stab wounds.
Defence QC Neil Murray, representing Smith, said that she was a vulnerable young woman who had had a horrific upbringing and childhood.
He told the court: "Miss Smith continues to deny any involvement in the death of Mr Blackwood."