This Is Us Star Justin Hartley Talks Kevin's 'Very Dark and Unfortunately Familiar' Relapse

This Is Us has delivered yet another heartbreaking ending.

After discovering that his beloved father Jack had lied to him about Nicky’s existence, Justin Hartley‘s character Kevin went back to the bottle. Kevin was dealing with a lot emotionally: He thrust himself into a new (and fast-moving) romance with Zoey (Melanie Liburd), and his thoughtful efforts to help his veteran uncle get back on his feet were unsuccessful.

In addition, it was a solo mission for Kevin as his siblings Kate (Chrissy Metz) and Randall (Sterling K. Brown) were busy preparing for their own life-changing moments: she’s expecting her first child and he’s getting ready for a new job as a councilman.

Though he was trying so hard to be the loving Pearson family member that Nicky never had, Kevin was unable to move Nicky out of his trailer and into a veterans center (a solution that Kevin thought was better for his uncle). In true Kevin fashion, he once again put expectations on himself that went unfulfilled.

RELATED: This Is Us: Why Jack Kept Brother Nicky a Secret — and How It ‘Profoundly Affected’ Him

Feeling defeated during his visit to Nicky’s trailer, Kevin called his girlfriend, thinking he had one person he could depend on. However, his phone call went to her voicemail. Unable to be reassured and talk through his feelings, Kevin spotted a bottle of whiskey in Nicky’s trailer and relapsed, chugging the liquor.

“I think it was a cry for help,” Hartley tells PEOPLE of his unanswered phone call to Zoey.

“If Zoey would’ve picked up, I wonder what would’ve gone on, you know? Maybe she would’ve been able to talk him out of it,” the actor says of an alternate ending. “Or if he just heard her voice and her say, ‘I love you’ or ‘come home.’ It’s one phone call.”

Hartley adds, “Zoey was probably at a yoga class!”

RELATED: What’s to Come in This Is Us Season 3: ‘Her’ Is Revealed, Nicky’s Fate and Kate’s Baby Boy

Alcohol has been a vice not only for Kevin, but also for Jack.

When Kevin was growing up, he thought his dad was perfect. However, he learned in season 2 that Jack had a problem with alcohol. In a way, learning that Nicky was, in fact, still alive was another example of Kevin feeling betrayed by someone he considered to be his hero.

What made that scene even more heartbreaking? No one in his family, not even Nicky, knows about his relapse.

“I’m really grateful to you because if it wasn’t for you, I wouldn’t be able to think of your father … thank you for that. I’m really proud of you, Kevin,” Rebecca (Mandy Moore) said during a mother-son car ride home, completely unaware of her son’s downfall.

“Kevin was feeling overwhelmed at that moment. He started seeing himself being sucked into a way,” Hartley says of the relapse scene, referencing seasons 1 and 2, when Kevin was hiding in hazes of pills and alcohol.

“It was a very dark, uncomfortable and unfortunately familiar place to feel,” adds Hartley, who called his character a “hot mess.”

Will it be downhill for Kevin in the second half of season 3? Fans will have to wait and see, as next week’s episode centers around Beth (Susan Kelechi Watson) and her backstory.

This Is Us airs Tuesdays (9 p.m. ET) on NBC.