The greatest harm facing polygamous women is the law outlawing their marriages, an advocate of polygamy and former plural wife told a B.C. court Thursday.

Mary Batchelor is a self-described "independent fundamentalist Mormon" who, a few days before her 21st birthday, became the second wife in a polygamous marriage while living in Utah.

The first wife left just three years into the marriage, later becoming a vocal critic of polygamy, and Batchelor and her husband have been living in a legal, monogamous marriage ever since.

Nevertheless, Batchelor said she has positive memories of her plural marriage, and hopes to one day welcome another wife into her family.

"We had some very good times, some really positive times, she and I had some strong bonding moments together," Batchelor, now 42, testified at court hearings examining the constitutionality of Canada's anti-polygamy law.

"We hope to be able to live plural marriage again. I did not choose monogamous marriage, I chose plural marriage. When that plural marriage ended, it broke my heart."

Batchelor grew up in a mainstream Mormon household with monogamous parents. In her late teens, she said she began researching fundamentalist Mormonism and decided she wanted to practise polygamy -- something the mainstream church renounced more than a century ago.

She wasn't connected to any specific religious sect, such as the Fundamentalist Church of Jesus Christ of Latter Day Saints, also known as the FLDS, and she didn't live in one of the closed polygamous communities that have been subject to intense scrutiny at the constitutional hearings.

Batchelor said she never experienced the physical or sexual abuse that experts and former polygamists have described during the court hearings, and said the only harm she faced was the constant fear of prosecution under Utah's anti-polygamy law.

"That was obviously very frightening to me and very scary, but I felt I had to do what was right and honour my own conscience," she said.

"I felt it was very oppressive and frightening to me. I wasn't able to tell people who my husband was and live openly. The feeling that you can't just live openly and be part of society for fear you're going to be prosecuted and your family is going to be torn apart."

Batchelor said she didn't agree with the practices of some fundamentalist Mormon groups, such as arranged marriages and teenage brides, but she said polygamy should be decriminalized. It would be better to educate polygamists about incest, underage marriage and sexual assault, she said, and use existing laws to deal with abuse.

Lawyers for the B.C. and federal governments pointed out that Batchelor was not an expert and only lived in a plural marriage for a period of three years nearly two decades ago. They also noted she has become a fierce critic of polygamy opponents -- notably her husband's ex-wife, Vicky Prunty.

Prunty, who is now the director of Tapestry Against Polygamy, has publicly said she left the marriage nearly 20 years ago because she was unhappy. In a story recounted in a book titled "God's Brothel," Prunty describes her ex-husband as abusive and controlling.

Passages of that book were read in court and Batchelor denied all of Prunty's claims, noting "God's Brothel" uses pseudonyms for Batchelor and her husband.

"There is a reason our names are not on this product -- we would sue," she said, shaking her head.

B.C. government lawyer Karen Horsman produced a letter Batchelor sent the offices of Tapestry Against Polygamy, which sarcastically derided Prunty as uneducated and incoherent.

"I suggest to you, Ms. Batchelor, that these writings are the writings of someone who is not open to considering contrary views," said Horsman.

"I had a hard time during that period, she was really mean to us," replied Batchelor.

The constitutional case was prompted by the failed prosecution of two leaders in the polygamous community of Bountiful, B.C.

Winston Blackmore and James Oler were each charged in 2009 with one count of practising polygamy, but those charges were later thrown out on technical legal grounds.