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PA
The jury has retired to consider its verdict in the case of a teacher accused of having sex with a 16-year-old pupil in a plane toilet.
Eleanor Wilson, 29, of Dursley, Gloucestershire, denies four counts of sexual activity with a child under 18 while in a position of trust.
She is accused of having sex with the boy on a school trip in 2015.
A former housemate told Bristol Crown Court her on-off relationship with her partner had been violent at times.
Alex Knight, who shared a house with Miss Wilson at York University in 2008 and 2009, said he felt compelled to give evidence after reading Andrew Hall's testimony in the media.
He said up until last week he had not spoken to her since late 2016 or early 2017.
He described Miss Wilson's relationship with Mr Hall as "extremely dysfunctional", and believed Mr Hall had "anger management issues".
He said: "There were lots of arguments I witnessed in the time they were living with us.
"On a night out he shouted at her in a fit of rage."
'Controlling'
He also said he once noticed finger marks on Miss Wilson's arm after she had driven Mr Hall home.
Mr Knight said he recalled a pregnancy scare when he had taken Miss Wilson to buy pregnancy tests.
He said this made him feel awkward when he was with her and Mr Hall at a later date and the conversation turned to pregnancy.
"The tone of the conversation changed very drastically and Andy became very angry," he said.
Miss Wilson previously denied telling the boy she was pregnant with his child and was planning to abort it.
However she admitted that she confided in the boy that she was pregnant by Mr Hall.
Miss Wilson said she did not reveal her pregnancy fears to her partner because she was afraid of his reaction.
She said Mr Hall was "controlling" and "abusive" and she only told the boy because she "wanted someone to feel sorry for her".
The case continues.