OTTAWA -- The assault trial of former Afghanistan hostage Joshua Boyle faces a possible delay of several months due to legal wrangling over allowable evidence.

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

The offences are alleged to have occurred in late 2017 after the couple returned to Canada following five years as hostages at the hands of extremists who seized them during a backpacking trip to Asia.

Coleman's lawyer, Ian Carter, says he will ask the Supreme Court of Canada for permission to challenge a ruling handed down Wednesday that allows Boyle to introduce evidence concerning certain consensual sexual activity with his wife.

The ruling is important because the law sets out limits on the extent to which an accused person can bring up an alleged victim's sexual history during a trial.

Carter plans to ask the judge presiding over Boyle's trial for a stay of the ruling while the Supreme Court process plays out -- a move that could effectively put the criminal proceedings on hold for several months.

Coleman has testified her husband spanked, punched and slapped her during their captivity, and that his violent ways resumed shortly after release.

Boyle was arrested in Ottawa in the early hours of Dec. 31, 2017, after Coleman told police he had assaulted her on numerous occasions.

During cross-examination, Boyle's lawyer, Lawrence Greenspon, has meticulously dissected Coleman's allegations.

However, uncertainty arose as to whether certain elements could be raised during the trial.

Judge Peter Doody ruled Wednesday that Boyle will be permitted to introduce evidence that he and Coleman engaged in "prior acts of consensual anal intercourse, consensual vaginal intercourse from the rear, sexual acts involving ropes and consensual biting as acts of sexual play."

Doody said the evidence will be limited to the general nature of such acts, and will not include significant details of any particular act.

Carter said he plans to ask Doody at a hearing next Wednesday for a stay of the ruling while Coleman's appeal proceeds.

Given that the Supreme Court can take months to decide whether to hear an appeal, "even on an expedited basis, it would appear it would delay matters for at least a number of months," Carter said.