Nicholas Gough, 59, was employed as a science teacher in a school before being put behind bars in March after admitting having assaulted his wife of 24 years Lynne during a quarrel. It left her disfigured for life, Daily Mail reported.
But Gough, of Wolverhampton city, is now planning to marry Anne Carr, 54, a divorced grandmother from Worcestershire, once he is released from Featherstone Prison.
Carr, a retired local government worker, met Gough last February on an internet dating site while he was still living with wife Lynne, 52.
The pair, however, got engaged May 11 during one of Carr's regular visits to Featherstone Prison. "I believe he's a good man and I'm going to stand by him. There are two sides to this story, and I feel Nick's in prison for something he didn't commit.
Lynne moved in with another man, claiming her husband had been violent towards her.
Gough had threatened to kill Lynne and tried to strangle her following the frenzied attack in a gazebo in their back garden after drinking a bottle of wine
He swore at Lynne and held her down on the floor, before sinking his teeth into the tip of her nose.
After the attack in September, 2011, Gough urged his wife to tell people that her injuries were inflicted by their pet dog.