A NSW woman who vanished in 2012 had messaged she was pregnant to Jim Church but he "doesn't want it", his murder trial has been told.
Leisl Smith also messaged that he cheated on his girlfriend with her, saying: "I should not have done what I done last night but at the end of the day I do love him".
Kobie-Rose Palmer gave evidence on Thursday about contact, including numerous messages and threats, she had with Ms Smith.
The 23-year-old vanished from the Central Coast on August 19, 2012.
James "Jim" Scott Church, 51, has pleaded not guilty in the NSW Supreme Court to murdering Ms Smith, whose body has never been found.
The Crown alleges the then-farrier killed her after she told people she was pregnant to him and because he wanted to save his new relationship with Belinda Lees.
But the defence contends Ms Smith's former partner Craig Elkin, who has since died, was a viable suspect while bikies also could have been involved.
The defence also disputes that Church wanted his relationship with Ms Lees to "flourish" and financially benefit from her wealthy parents.
Ms Palmer said she was a friend of Ms Lees and used to agist her horse on her property, but her relationship with Ms Smith was "very up and down".
Sometime after they had a dispute about Ms Smith talking to Ms Palmer's partner, Ms Palmer said Ms Smith had rammed her car into oncoming traffic.
In June 2012 after Ms Lees and Church were seeing each other, Ms Smith messaged to say "I'm five months pregnant to Jim" and "I have lost him as a best mate because of that dog".
Another message said she even knew when they had sex and "he texted me straight after".
Ms Palmer said she had concerns about Ms Smith who made threats about her family and horses, but while she was very scared she knew Ms Smith was an animal lover.
She said she asked Ms Smith if she was in a relationship with Church.
She replied "nah, not really, been with him two years, he told me he was getting a gf, we were most best mates".
Ms Smith wrote that Jim knew the baby was his but "doesn't want it though".
Ms Palmer said she doubted Ms Smith was pregnant, but after she asked for pictures she got one where she could see her baby bump.
She said she talked with Ms Lees about being in Facebook contact with Ms Smith about things, including her pregnancy.
Days before she vanished Ms Smith messaged to say she had cheated with Jim "up the bush" last night.
Under cross-examination, she agreed Ms Smith had threatened to kill herself.
She also agreed that on one occasion when Ms Smith said she was having sex with Church, she knew it was untrue as he was present with her and Ms Lees.
Earlier, Ms Smith's mother Sandra Harvey said after she had a car accident in 2000 their four children went to live with her ex-husband Storm Smith.
She had limited contact with her daughter in the lead-up to her disappearance.
But she knew Ms Smith had a relationship with an older man, Craig Elkin, with whom she moved in when she was 18.
She was shocked when her daughter told her he was running drugs for a bikie gang.
Her daughter also said he was abusive to her, but said "you can't help who you fall in love with".
The judge-alone trial, before Justice Elizabeth Fullerton, continues.
