Mervyn Annear, 65, bashed his estranged wife Charma Annear over the head with a pot before killing her and dragging her bloodied body outside in November 2016.
The 30-year-old victim was six months pregnant to her new partner Brian “Charlie” Haggarty and the couple had recently stocked up on baby items for their child.
Annear claimed he loved his estranged wife to the end, arguing he may have accidentally suffocated the 50kg woman when he lay on her during a fight in a bid to restrain her.
After a four-day trial and 2½ hours of deliberations, a Supreme Court jury found Annear not guilty of murder and convicted him of the lesser charge.
Annear was seen lurking near the Filipina woman’s home in the lead-up to her death and he knocked on her front door about 5.30am after Mr Haggarty left for work.
The victim’s cause of death could not be established but a forensic pathologist found Ms Annear had haemorrhaging that could have been caused by compression to the neck, chest or abdomen.
Annear dragged his former partner’s body outside after the killing then he stole her car, purse and other belongings.
He told the jury he wanted to get help for the victim but said he could not lift her into the car because he was tired and had the lung capacity of a child.
Annear did not call triple-0 or go to the nearby hospital for help, which prosecutor Bernard Standish said was about two minutes away by foot.
The killer testified he did not know Ms Annear was pregnant, but Mr Standish said that statement beggared belief.
Annear said he told his ex, who was in Australia on a spousal visa, that she was stuck with him for good because he would never divorce her.
Annear will be sentenced next month.
This article originally appeared on The West Australian.