A Crown prosecutor says testimony about former hostage Joshua Boyle's controlling, abusive nature should be admitted into evidence at his assault trial because it depicts a relevant pattern of behaviour.

Boyle, 35, has pleaded not guilty in Ontario court to offences against estranged spouse Caitlan Coleman, including assault, sexual assault and unlawful confinement.

The offences are alleged to have occurred in Ottawa in late 2017 after the couple returned to Canada following five years as captives of extremists who seized them in Afghanistan during an ill-fated backpacking trip.

However, Crown prosecutor Meaghan Cunningham told Judge Peter Doody, who is hearing the case without a jury, that the criminal proceedings must take into account the complete context of the couple's relationship.

"The point of this evidence is it shows a pattern of behaviour," Cunningham said Monday.

Boyle's lawyer, Lawrence Greenspon, argued such evidence should not be allowed, saying it was insufficient to contend his client was generally inclined to act abusively toward Coleman.

Coleman has testified that her husband regularly punished her with spankings for arguing with him or disobeying his wishes.

She recounted how the two met online when she was 16 and began an on-and-off relationship before marrying in 2011 in Costa Rica and travelling the following year to central Asia.

She said that in the early days of their tumultuous courtship, her future spouse would often belittle her. Over time, he told her how to behave and what to wear. Emotional and verbal abuse later became punches and slaps to the face, Coleman said.

Witnesses at the trial have described Boyle as angry and domineering in the days following his release from captivity.

Janice Unger, a Global Affairs Canada official who accompanied them on the plane back to Canada, told the court that at one point during the flight Boyle abruptly demanded that she and a colleague return to their seats.

Coleman's sister, JoAnn Rotenberry, visited the couple shortly after their return and recalled that Boyle always seemed upset and frustrated, and would speak to Caitlan in a demeaning way.

Coleman's mother Lynda testified she felt her daughter was afraid of upsetting Boyle and catered to him and the children while he did nothing to help.

Greenspon suggested the Crown would need to do more than demonstrate Boyle had a "bad attitude" in Ottawa for the testimony to become part of the evidentiary record.

He questioned how prosecutors could draw a direct line from such testimony to the alleged commission of criminal offences. In turn, he wondered how any of it added an essential thread to the narrative, warranting admission into evidence.

"In my submission, it doesn't," Greenspon said.

The Crown's first witness, social worker Deborah Sinclair, testified in March about how an abuser's controlling behaviour can damage a woman spiritually and emotionally, affecting how she acts.

Sinclair has worked for decades on issues of trauma and intimate partner violence, but the defence questioned the extent of her expertise.

In a ruling Monday, Doody said Sinclair's evidence with respect to the behaviour of victims of captivity would not be admitted.

Keep reading