A thug who waterboarded his lover while she watched an episode of Friends was jailed for 50 months.

Scott O'Sullivan, 40, made the woman suffer at his hands during a six-year campaign of domestic terror.

O'Sullivan, of Glasgow's Drumchapel, kept tabs on the woman and attacked her on several occasions.

This included slamming her face onto a mirror and sticking a knife into her hand.

The woman told a jury that O'Sullivan also tried to drown her by putting a towel over her face and pouring water on it.

She stated that she struggled to breathe and felt she was going to pass out.

She later ended the relationship but found out he started a romance with her teenage half-sister.

Her half-sister was also a victim at the hands of O'Sullivan who tormented her for two years.

O'Sullivan was violent towards her while she was pregnant and made her "feel like nothing."

The half-sister stated O'Sullivan used steroids which made him aggressive and recalled a cigarette being put out on her arm.

O'Sullivan was found guilty at Glasgow Sheriff Court to assaulting the woman to her severe injury and permanent disfigurement.

The charge spans between 2004 and 2010 at properties in the city's Summerston, Anniesland and Maryhill.

He was also convicted of assaulting the other woman at a property in Summerston between August 2012 and May 2014.

Sheriff Patrick Hughes imposed a five-year extended sentence where O'Sullivan will be under supervision upon his release from prison.

He said: "Both charges you were convicted of are of extreme and serious nature...a troubling aspect is asphyxiation which is viewed as serious by the courts.

"On the other charge, the harm is less serious but there has been a degrading and humiliating element which has aggravated it.

"Having regard to all factors, there is no alternative to custody.

"Having regard to the background report which is deeply troubling - among the most troubling I have read in a case such as this - the normal period of licence on release is insufficient."

The court heard from the woman who stated she got into a relationship with O'Sullivan who she met through work.

She claimed that the waterboarding incident was in 2004 or 2005 while she was sitting on the couch watching an episode of Friends.

She told police in a statement: "He had an argument with me.

"He came up behind me with a wet towel and put it on my face from behind then pulled my head back.

"He then started pouring a bottle of water over my face trying to drown me...I couldn't catch my breath, I thought I was ready for passing out."

She said she later broke down in tears before putting pyjamas on and went to bed.

The witness stated that they initially split up but got back together.

She stated that O'Sullivan called her names such as "ugly."

However, the pair got married in 2008 and she found a job at Barclay's bank.

She stated that O'Sullivan was "jealous" of her and believed she was going to cheat on him.

But, she later stated that it was O'Sullivan who cheated on her with a barmaid.

She recalled having her head slammed on a mirror by O'Sullivan which resulted in swelling.

She added that O'Sullivan became "animated" and put a kitchen knife through her hand in 2009.

She stated that she broke up with O'Sullivan in 2011 after she "snapped" and did not want to go home to him.

Prosecutor Lauren Donnelly asked: "Did you find out that he entered a relationship with your half-sister?"

The woman replied: "Yes" adding that she was 17 and had known O'Sullivan since she was six.

Her half-sister stated she got into a relationship with O'Sullivan a year after he split with her sister.

She stated that it was "brilliant at the start" and became pregnant for the first time.

O'Sullivan was stated to have struck her with a Moses basket with such force that it broke.

She fell pregnant again in February 2013 and was violent towards her.

The charge states she was seized and dragged by the hair.

She was also repeatedly kicked on the body.

Further to this, she was repeatedly kicked, slapped and punched on the body.

Prosecutor Lauren Donnelly told jurors in her closing speech: "The half-sister said: 'I felt as if someone who was there to protect me was hurting me more than anyone else had ever done'."

The jury was also reminded that her half-sister told them that O'Sullivan was aggressive and using steroids.

Miss Donnelly added: "She described an incident when they had been arguing and he stubbed a cigarette out on her arm."

O'Sullivan also accused her of cheating on him and the half-sister claimed the relationship took a toll on her mental health.

She reported the matter to the police without consulting her half-sister.

A 10-year non-harassment order which prevents O'Sullivan's contact with the women was also granted at the sentencing.