O’FALLON, Mo. — With three small children and her marriage in trouble, Pat Bond attended a spirituality retreat for Roman Catholic women in Illinois 26 years ago in hopes of finding support and comfort.

What Bond found was a priest — a dynamic, handsome Franciscan friar in a brown robe — who was serving as the spiritual director for the retreat and agreed to begin counseling her on her marriage. One day, she said, as she was leaving the priest’s parlor, he pulled her aside for a passionate kiss.

Bond separated from her husband, and for the next five years she and the priest, the Rev. Henry Willenborg, carried on an intimate relationship, according to interviews and court documents. In public, they were both leaders in their Catholic community in Quincy, Ill. In private, they functioned like a married couple, sharing a bed, meals, movie nights and vacations with the children.

Eventually, they had a son, setting off a series of legal battles as Bond repeatedly petitioned the church for child support. The Franciscans acquiesced, with the stipulation that she sign a confidentiality agreement. It is now an agreement she is willing to break as both she and her child, Nathan Halbach, 22, are suffering from cancer.

With little to lose, they are eager to tell their stories: the mother, a once-faithful Catholic who says the church protected a philandering priest and treated her as a legal adversary, and the son, about what it was like to grow up knowing his absentee father was a priest.

“I’ve always called him Father Henry — never Father, never Dad,” said Nathan, at home between hospital visits. “I always felt he picked religion over me.”

The relationship between Bond and the priest is hardly unique. While the recent scandals involving the Roman Catholic Church have focused on the sexual abuse of children, experts say that priests who have violated sexual and emotional boundaries with adult women are far more common.

Clergy members of many faiths have crossed the line with women and had children out of wedlock. But the problem is particularly fraught for the Catholic Church, as Catholics in many countries are increasingly questioning the celibacy requirement for priests.

Bond’s case offers a rare look at how the church goes to great lengths to silence these women, to avoid large settlements and to keep the priests in active ministry. She has 23 years of documents, depositions, correspondence, receipts and photographs relating to her case, which she has kept in meticulous files.

Those files reveal that the church was tight-fisted with her as she tried to care for her son, particularly as his cancer treatments grew more costly. But they also show Willenborg suffered virtually no punishment, continuing to serve in a variety of church posts.

The church entity Bond dealt with is the Order of Friars Minor, commonly known as the Franciscans, whose members were known as mendicants because they survived on handouts from the communities they served.

“I know better than Franciscans what it’s like to beg, because nothing has happened without my begging the Franciscans,” said Bond, 53.

Church officials, however, say they acted generously.

“The province went well beyond what the law would require, and was concerned for the boy and his well-being,” said the Rev. William Spencer, provincial minister of the Franciscan Province of the Sacred Heart, which is Willenborg’s province in St. Louis. “We were willing to do whatever we could to respond to him.”

The father

The priest Bond fell in love with so many years ago, Willenborg, is currently the senior pastor of Our Lady of the Lake, a large, historic parish of 1,350 families on the shores of Lake Superior in Ashland, Wis. The church spire is visible from miles away, and the parish operates an adjoining school. On a recent Sunday, Willenborg affably led a morning Mass for about 300 people, adding a special blessing for the grandparents in the congregation. Afterward, in his office, he acknowledged that he does have a son, is aware his son is terminally ill, and said that he had tried to be attentive.

He said he did not want to talk about the situation, and pointed out that Bond had more to lose than he did because she had signed a confidentiality agreement that, if broken, requires her to pay a penalty. He asserted that Bond had shown no care for his needs and was only concerned about money, and that his son had shunned him. He said he and the Franciscans had done nothing bad.

“We’ve been very caring, very supportive, very generous over these 20-something years. It’s very tragic what’s going on with Nathan, but, you know?” said Willenborg, before trailing off and ending the interview.

Before their baby was born, the Franciscans strongly advised Bond to give it up for adoption, correspondence shows. She refused.

“What would I say to my other children, after coming home from the hospital: ‘I’m sorry, I forgot to bring your family member home?’” she said.

Willenborg himself performed the baptism. Bond named the boy Nathan John Paul Halbach, giving him the last name of her former husband, who was still an involved father to the three children they had together and supported them financially.

Bond retained a lawyer, and the Franciscans gave her $1,000 toward the costs of the birth that were not covered by insurance, and $505 toward baby furniture. The Franciscans further agreed to pay $600 a month for the baby’s first 10 months, until Bond could return to work in a travel agency, and after that $350 a month in child support until Nathan turned 18. It added up, after bank and legal fees, to about $85,000 paid in a lump sum.

For eight months, Willenborg continued to visit Bond’s home at night. She said he would go right to the crib, pick up the baby and bring him to the bed to cuddle with them.

An unexpected turn of events brought their idyll to an end. A young woman showed up at Bond’s house in a rage. She told Bond that she had been in a sexual relationship with Willenborg for years, since she was in high school. Immediately, the Franciscans sent Willenborg to a treatment center in New Mexico for priests with sexual disorders and substance addictions.

Seeking support

Bond, meanwhile, got help from a support group for women and priests involved in relationships. The group, Good Tidings, was founded by Cait Finnegan and her husband, a former Catholic priest, originally with the idea that they would help priests who had fallen in love to discern whether to leave the priesthood and marry, or remain in the priesthood and end the relationship.

“We were naive,” Cait Finnegan said. “We quickly discovered that many of these priests were playboys.”

She said that in 25 years, Good Tidings had been contacted by nearly 2,000 women who said they were involved with priests, many who had signed child support and confidentiality agreements similar to Bond’s.

Willenborg had no contact again with his son until the boy was 13. Nathan remembers being so excited to finally meet his biological father that he insisted on getting a haircut. He remembers that Willenborg took him to McDonald’s and to see the movie “What Women Want.”

Nathan recalled, “It was sort of hard meeting this guy for the first time, at a place where we couldn’t talk to each other.”

The child support money had run out long before Nathan turned 18. Bond had used $38,000 of it as a down payment on a house. She remarried, twice, and her last husband was a lawyer who encouraged Bond to petition the Franciscans for money to help send Nathan to college.

The Franciscans resisted, and they ended up in court. Willenborg insisted on a DNA test, which showed the probability of paternity was 99.9 percent. “That really pushed me away further,” Nathan said. “It was ridiculous. He knew I was his son.”

After months of court proceedings, the Franciscans agreed to pay half of Nathan’s college expenses, plus $586 a month, until he turned 21.

With the costs mounting for chemotherapy, radiation and craniotomies, Bond again turned to the church. The Franciscans agreed to pay 50 percent of any “extraordinary” medical costs, until he turned 23. Bond said she was greatly relieved.

She finally found a doctor at Memorial Sloan-Kettering Cancer Center in New York City who proposed an experimental treatment on Nathan’s tumors, which had returned despite all the previous treatments. They flew to New York for a one-week consultation, and ended up staying for three months while he was in and out of the hospital for treatment.

The Franciscans initially gave them $1,000 toward the trip, but then refused Bond’s further requests for reimbursements for lodging expenses for her and Nathan in New York. This is what pushed her over the edge, she said. Dozens of e-mail messages between Bond and church lawyers document the back-and-forth. Catherine Schroeder, the Franciscans’ lawyer, said Bond failed to provide proper receipts, an accusation that Bond denies.

The head of the province then was the Rev. Michael Perry, who was recently elected vicar general of the entire Order of Friars Minor. Reached in his office in Rome, Perry declined to speak on the record, except to say, “Efforts were made not only to respect the law but to take into account the dignity and the rights and the care of the child.”

Nathan is now so ill that he rarely leaves his house except for hospital visits. The highlight of his day is lumbering to the mailbox, leaning on his mother, who was told recently by doctors that she had carcinoid tumors in her appendix and colon.

Recently the mail included a card from Willenborg.

“I never understood,” Nathan said, “why he thought cards could make it all OK.”