Feng Lin testified that he and Lin, a university student from China, were lovers from late 2010 until mid-May 2012, about a dozen days before some of Lin's remains were found in trash outside a Montreal apartment building.
Feng Lin, a 35-year-old software company manager who travelled from China to testify, said their relationship ended because Jun Lin's family wanted him to settle down.
He said Lin's family did not know their son was gay.
"He was experiencing some pressure from his family and he was kind of obliged to go into a relationship with a girl for an eventual marriage," he said in response to a question from Crown prosecutor Louis Bouthillier.
Feng Lin described Jun Lin, 33, as a fitness buff who didn't smoke, drink or do drugs and who would go to the gym up to four times a week.
He said they were faithful to each other and that he loved Jun Lin. Their sexual relationship, he added, was normal and they were "not very interested" in pornography.
Asked whether they were into bondage, he replied through a Mandarin translator, "Absolutely not."
He said he knew Jun Lin used Grindr, a gay male social networking application where people can meet others.
In cross-examining Feng Lin, defence lawyer Luc Leclair sought to paint the deceased as a sexually promiscuous individual with a keen interest in S&M videos and who posted dark messages on a Chinese social media site.
Leclair suggested that Feng Lin didn't know his partner very well.
He referred to Internet logs from Jun Lin's computer that showed he had downloaded a number of hard core gay porn videos bearing such titles as "Bare Back Vibes" and "Extreme Pleasures 2."
Confronted with stills from one of the movies, Feng Lin asked the judge at one point if it was necessary for him to view the graphic images.
Leclair then confronted the witness with Skype and other online chats that suggested Jun Lin had sex in person with a number of different men — after the breakup of their relationship.
"We had split up all that time already so he had all his freedom," Feng Lin said.
He said he knew that Jun Lin had been previously married and was divorced. When they lived together, Feng Lin paid the rent and some of Lin's meals.
While he'd met Jun Lin's parents, they'd never divulged details of their relationship to them. Feng Lin's parents were aware and accepted it.
Feng Lin, who has permanent resident status in Canada, left the country to return to China for the summer on May 13, 2012.
The witness testified they remained friends when the relationship ended and that he texted Jun Lin up to 50 times a day, with his ex-lover's last message coming on May 24, 2012. That was the day friends last saw the Concordia University student.
"He was saying good morning to me because it was a time when I just woke up," Feng Lin said.
Messages then sent by Feng Lin over the next several days went unanswered.
"I sent him a text message, and seeing there was no return on his part, I then sent him several others but these several others were not opened and not read," he said.
Lin decided to return to Canada early.
"I did see on the Internet there was the discovery of a body, but it didn't cross my mind," he said. While in transit, he was told by a friend about the appearance of an online video that appeared to show Jun Lin's body.
"Only when I arrived in Montreal, did I look at the first part of the video," Feng Lin said. But he testified he didn't believe it was Jun Lin.
Magnotta, 32, is charged with first-degree murder in Lin's slaying and dismemberment.
He also faces four other charges: criminally harassing Prime Minister Stephen Harper and other members of Parliament; mailing obscene and indecent material; committing an indignity to a body; and publishing obscene material.
He has pleaded not guilty to the five charges, although he has admitted to the acts. His lawyer has indicated he will mount a defence of mental disorder to seek a verdict of not criminally responsible.
Earlier on Wednesday, Leclair showed jurors many of the items collected in the trash outside Magnotta's apartment, including screwdrivers, a hammer, a hand-held saw, clothes, receipts, a jockstrap, a poster of the movie "Casablanca" and a felt red square that was prominent during Quebec's 2012 student unrest.
Leclair also conducted a similar exercise with several exhibits mailed to Ottawa and Vancouver that were subsequently transferred to Montreal police.
The trial, whch enters its fourth day Thursday, is expected to last between six and eight weeks and feature some 60 witnesses.
Bouthillier has told the eight female and six male jurors he intends to prove Magnotta planned the slaying. He said the evidence will show the accused killed Lin dismembered his corpse and sent his hands and feet by mail to Ottawa and Vancouver.
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