They say bad things come in threes. In the fall of 2008, Rosie Roberts and her sister were both diagnosed with cancer. Their elderly mother was ailing and near death. For Ms. Roberts’s family, three bad things seemed like plenty to deal with at once. But the bad news kept coming.

Ms. Roberts was notified shortly after her first lumpectomy that the procedure had failed. Two hours later, her mother died. With her family in mourning, her sister still in treatment, and Ms. Roberts preparing herself for another surgery, what she really needed was support.

She got that, and more, from her partner, Jon Lange. He became her caregiver through the ordeal, a job that included keeping her family updated on Ms. Roberts’s progress, shuttling her back and forth to surgeries and doctor visits in Boston, and researching the details of the disease while trying to shield her from the burden of too much information.

On June 4 and 5, Ms. Roberts will take part in the American Cancer Society’s Relay for Life, as a cancer survivor. And like so many other survivors, she said that she wouldn’t be where she is today without her caregiver’s support.

“Jon really held everything together,” said Ms. Roberts, at her home in Vineyard Haven sitting next to her youngest daughter, Allison, and across from Mr. Lange one evening this week. During her five surgeries — unsuccessful lumpectomies, followed by a mastectomy, and finally reconstructive surgery — he kept their life organized in a shoulder bag that once belonged to Allison. It contained medical forms, documents for ferry travel, and contact information for family members, among other things.

“It’s Tuesday evening, and everything’s fine. Wednesday comes and the world has changed,” said Mr. Lange. “You start having to just do these things. You need someone to be the health advocate, to get the information . . . [and] to be by her side when people are telling her about what’s going on with her body.” He continued:

“When it starts feeling like you’re not doing enough, or you don’t know what more you can do, you’ve got to keep telling yourself that you are and you don’t realize it, because you’re there.”

Ms. Roberts will walk the relay for her second year as part of the team Center for Living, where she works, to raise money to find a cure for cancer. But she will also walk in part to honor the man who stood by her through her treatment and recovery.

The Relay for Life begins at 3 p.m. at the Martha’s Vineyard Regional High School track, and continues through the wee hours and into the following morning. It will be the seventh annual relay on the Vineyard. The relay is the largest grassroots fund-raising effort in the world, with events held in thousands of communities across the country. In Massachusetts alone, relay walkers raised more than $10 million in 2009 to honor the lives lost to cancer, survivors, and patients still suffering.

Leslie Look is living the new normal, as she calls it, as her husband, Chris, recovers from non-Hodgkin’s lymphoma. It’s not been easy to get out, she said Monday, taking a brief break from her busy day to grab a bite to eat in an Edgartown coffee shop. But like the millions of others across the country and world touched by cancer, it has helped her family appreciate small miracles.

Mr. Look has been cancer-free for nine months now, but the treatment process and recovery from two stem cell transplants was grueling. “He went through a year that was not so great afterwards. It was hard on him, which made it hard on me,” said Mrs. Look.

At one point, Mr. Look had to stay in a hospital room for five weeks. Because he’s claustrophobic, Mrs. Look said she worried he wouldn’t make it. “We thought it was going to be torture,” she said. But she did everything she could to keep her husband feeling less closed-in and more at home, from throwing open the windows to decorating the room with pictures and reminders of the outside world.

Like other Vineyarders dealing with cancer, Mrs. Look said the commute from Boston was the hardest part. The race to catch the boat was a constant struggle, from battling traffic to dealing with a sick patient in the passenger seat. She’s thrilled that oncologists are establishing outlets for treatment that will be more accessible to Islanders, and she said the Steamship Authority is always looking for ways to make the travel more convenient.

Mrs. Look will walk the Relay for Life as part of the Martha’s Vineyard Cancer Support Group team, which offers financial assistance to families dealing with cancer. And though she never asked for any money from them during her ordeal, she knows how important that element is in the struggle. One of her greatest burdens to shoulder in caring for her husband was financial. The family’s monthly health insurance costs were enormous, and tacking on ferry fees and hotel costs, even at discounts, along with a handful of co-payments at each visit, just made it worse. Mr. Look was out of work and her photography business had plummeted since the diagnosis.

Now, she’s trying to get her own life back on track, and trying to spread the word that she’s looking for photography work. She’s also becoming active in the community again, among other things working on bringing new recreational opportunities to the Island. But most important, she said, is that this experience has strengthened her relationship with her husband. “I realized that it was one of the hardest things I’ve ever had to do,” she said, “but it kind of changed our dynamic.”

Unlike Mrs. Look and Mr. Lange, the cancer patient that Mike Cassidy cared for was his young daughter, Samantha Cassidy, who was diagnosed with lymphoma at age seven. He and his wife, Debbie Grant, took care of their daughter through the diagnosis, which came a week before Mike’s older daughter’s wedding was to be held at their home. Samantha was the flower girl for her big sister, and three days later, she went into the hospital for her first surgery, followed by two years of treatment. “It was pretty horrific,” said Mr. Cassidy, describing the chemotherapy and steroid treatments. To make matters worse, Samantha’s treatment was complicated by adverse reactions to some of the drugs, and a case of shingles.

“You take everything in your life, and divide it into two piles: the important stuff and the unimportant stuff,” said Mr. Cassidy. “Taking care of Samantha was the important pile. Everything else was unimportant.”

For Mr. Cassidy, remaining a steadfast caregiver to his young daughter meant that he needed support himself. He joined the Island cancer support group right away. “I just knew it was not something to be dealt with alone,” he said. “It seems almost like you’d want any break you can get from talking about cancer, but it’s great, once a week, to be with other people who have been through it . . . And it’s nice, once a week, to be able to fall apart if you need to.”

At the relay, Mr. Cassidy will walk as part of the cancer support group team, alongside Mrs. Look. This will be his second year participating, and he hopes for many more. “This year, I’m pitching a tent and sleeping out overnight,” he said. “The Relay for Life, I think I’ll make sure that it’s a part of my yearly repertoire.”