From PEOPLE Magazine Click to enlarge
Cindy Hawke-Renn wanted to make sure the birthday celebration she and her parents were throwing for Dr. Bill Petit Jr., her late sister's husband, was quaint and special. It was going to be a small gathering at a Cheshire, Conn., bed-and-breakfast. "We said, 'You can invite your parents or a date or whoever you want," she recalls. When Petit walked into the party on Sept. 23 with a pretty blonde, Hawke-Renn could only smile. "Mom, Dad and I have said to him since early on, 'We want you to date again,' " she says. A few minutes after arriving at the party, Petit took Hawke-Renn aside to tell her the woman, Christine Paluf, was more than a date-she was someone he was thinking of having a family with. "I said, 'Go for it,' " she recalls. "This was something we hoped and prayed for, that Billy would one day find love again."

Five years ago that was almost unthinkable. In 2007 Dr. Petit's wife, Jennifer Hawke-Petit, 48, and two daughters, Hayley, 17, and Michaela, 11, were murdered in a horrific home invasion in Cheshire, while Petit, helpless, was tied up in the basement. Devastated, Petit, a diabetes specialist, gave up practicing medicine, moved back in with his elderly parents and devoted himself to keeping his family's memory alive and seeking justice for their killers. "The impact of these crimes against our family was and is like a bomb going off in your house," Petit said in November 2010. It "completely shattered my life." But on Dec. 30-just three weeks after a jury approved the death penalty for Joshua Komisarjevsky, the second man involved in the murders-Petit, 55, marked the true end to that long, painful chapter and proposed to Paluf, 34, a photographer he met in 2008 at a local country club, where she worked as a marketing director. Friends and family say the newly engaged couple are quietly blissful. "He's happier and more joyful, lighter," says Hawke-Renn, 51.

It took him a while to get to this place. After the couple first met, Paluf offered to donate her photography services to the Petit Family Foundation (petitfamilyfoundation.org), which Petit founded in the wake of the murders. The two spent hours together, but love didn't bloom until last summer. "It just kind of happened," says Kendra Dull, 35, Christine's best friend. "They realized they both had feelings for each other."

Even then, the idea of moving on was difficult. After introducing Paluf to his family at that fall birthday celebration, he tearfully confided his deepest fears to Hawke-Renn. "I just don't know if I can love and cherish other children as much as I loved Hayley and Michaela," Hawke-Renn says he told her. "I said, 'Of course you would. Billy, when you have another child you always wonder if you can love the next one as much as the one you have. And you do.'"

He also got his former father-in-law's blessing. "I said to Christine, 'I would accept you as my daughter,' " says Rev. Richard Hawke, 80. Perhaps most important of all, he has some assurances that his girls would approve. Elizabeth Ollero, 16, his daughter Michaela's best friend, who started the website forevermichaela.com, says, "Michaela would want her dad to get remarried and recover and feel better. She wouldn't want her dad to be sad for the rest of his life."

Those close to Petit say they have seen a real difference in him since Christine walked into his life. "He's gone through hell, and I think now he's looking forward to happiness and the future," says Ann Baldwin, Petit's friend. Still, Dull said no one is more sensitive to his grief than Paluf. "She just tries to be there for him, listen when he needs her to listen and cry with him when he needs her to cry."

Petit has one more ordeal to get through before he can truly embrace his future and start planning that wedding. On Jan. 27 he will give his victim-impact statement at Komisarjevsky's official sentencing. Christine will be with him, as she was throughout the most recent trial. "She knows that he loves her and that he loves Jennifer, Hayley and Michaela," says Dull. "She knows there's enough room in his heart for all of them."