"My marriage to Paula [Patton] was crumbling. I started using painkillers. It was a melting pot of trouble brewing, and I was so arrogant that I thought I could handle it all," the star tells PEOPLE

Robin Thicke is reintroducing himself.

On Friday, the singer, 43, is set to release his first new album in seven years, On Earth, and in Heaven, which he tells PEOPLE in this week's issue, on newsstands Friday, was born out of his current state of bliss as a dad of four.

"In some ways, I've never been happier," says Thicke, who shares daughters Mia, 2½, and Lola, 23 months, as well as son Luca, 8 weeks, with fiancée April Love Geary, and son Julian, 10, with ex-wife Paula Patton. "In many ways, I don't think I've ever been this happy. This album is a testament to all the love in my life and the people who have gotten me here."

Thicke's new chapter is much welcomed, but it's also bittersweet. Much of his last decade was filled with public drama stemming from a contentious divorce from Patton and a series of devastating losses, including the sudden deaths of his dad, Growing Pains star Alan Thicke, his manager Jordan Feldstein and his longtime mentor, music producer Andre Harrell.

"I sure wish I could share this place that I'm in right now and celebrate it with them," says Thicke. "But sometimes it takes time to get there."

Born and raised in Los Angeles by Alan and singer-actress mom Gloria Loring, Thicke was immersed in showbiz from the start. "I'm lucky I had a kind, and genuine individual to teach me the ropes," he says of his father.

At 17 he moved out of his family home and began writing and producing songs for artists like Brandy and Christina Aguilera. After Harrell took him under his wing, he released his debut album, A Beautiful World, in 2002.

While it was a commercial disappointment, Thicke's provocative lyrics and soft falsetto caught industry attention. Four years later, the then-fledgling star dropped his sophomore album, The Evolution of Robin Thicke, which topped the R&B charts, where Thicke also landed a No. 1 hit with "Lost Without U."

robin thicke
Robin Thicke
| Credit: Jack Buster/Courtesy Robin Thicke

Still, Thicke longed for crossover success, and his breakthrough moment came in 2013 when he teamed up with longtime friend Pharrell Williams and T.I. on their hit "Blurred Lines." The controversial track — whose lyrics and music video were deemed misogynistic by some — became the longest-running No. 1 single of the year after topping the Billboard Hot 100 for 12 consecutive weeks.

But as his career reached new heights, Thicke's personal life was falling apart.

"My marriage to Paula was crumbling," he says. "I started using painkillers. It was a melting pot of trouble brewing, and I was so arrogant that I thought I could handle it all."

After 21 years together and almost nine years of marriage, Patton filed for divorce in 2014. Alleging infidelity, physical abuse and drug use, the actress, 45, and Thicke battled in court over their son. (Thicke has denied the cheating and abuse allegations.)

"Everything seemed to burn down there for a few years," says Thicke.

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Indeed, after facing backlash over his infamous performance with Miley Cyrus at the 2013 MTV VMAs, Thicke took another hit when he, along with Williams, was sued by Marvin Gaye's estate for copyright infringement of Gaye's 1977 hit "Got to Give It Up" on "Blurred Lines." (In 2015, Thicke and Williams were ordered to pay $5.3 million when they lost the case.)

In his deposition, Thicke admitted to abusing pills and alcohol when "Blurred Lines" became a hit.

"That year was a whirlwind of fame, and overindulgence all coming to a head," Thicke — who says he initially began taking painkillers to manage "terrible" back pain from frequent flights across the world — reflects now. "The painkillers became part of the release."

"You don't realize you're not in control," he adds. "Fame and a lot of those things — they got to me. I was in a bad place. I'm happy to have closed that chapter."

robin thicke
Robin Thicke and Miley Cyrus in 2013
| Credit: Theo Wargo/Wireimage

The loss of his father to a fatal heart attack in late 2016 was a wakeup call, but Thicke admits he still struggled to get his life back on track.

"I wasn't in a good place when he passed, and I wasn't in a better place right after," he says. "However, a few months later I decided to dedicate my time to raising my son. I put everything aside. That was a big turn for me."

When he and Geary, 26 — whom he met six months after separating from Patton — lost their home in the Woolsey fire in November 2018, Thicke kept his father in mind.

"I was suffering blow after blow, loss after loss," says Thicke, who was months away from welcoming Lola at the time. "But I saw the house burning down as a chance for me to step up."

Robin and Alan Thicke
Alan and Robin Thicke
| Credit: Charley Gallay/WireImage

After a miscarriage, the couple were "elated" when Mia joined the family in 2018 — then Lola a year later. On his new album, Thicke sings about a boy growing into a good man.

"It's about the passing of the torch of my father to me, and the kind of man I want to be," he says. "It's no coincidence I've had three children in the last few years. Fatherhood has fed my soul and brought me back."

Currently building a new home, Thicke and Geary — who got engaged in 2018 — are looking forward to the day they can say "I do" safely after the pandemic.

"We wanted our daughters to be old enough to be flower girls," Thicke says. "Luca will be the ring bearer."

For now, Thicke — who will again appear as a judge on the upcoming season of Fox's The Masked Singer — is relishing extra time with his family.

"Every night we do a little prayer," he says, "and we thank God for all the people in ourlives. I'm just so grateful."

For all the details on Robin Thicke's new chapter, pick up the latest issue of PEOPLE, on newsstands everywhere Friday.