"One of the reasons Hailey knew he needed more help was his sleep patterns," the source says. "He's been sleeping far more than usual, and struggles to get out of bed until very late into the morning or early afternoon."
"It's very hard for Hailey to watch him suffer with the depression," the source continues. "She's been nothing but a good support system for him but she knows she isn't a professional, and steady therapy is exactly what he needs. She loves him dearly and hates to see him in pain. She just wants him to be at his healthiest so she pushed him to get steady help and he hasn't resisted."
The source says Justin had already been struggling with depression before he and 22-year-old Hailey got together again last year.
"Justin has battled depression for years and often found himself self-medicating," the source says. "He grew up very quickly and was constantly exposed to drugs and alcohol at a young age. In everyday life, he was either working or partying and finally it was all too much. He has lived a lifetime in his 24 years."
"He's mostly relied on his religion, his pastor and Hailey who have been there for him," the source continues. "He has been seeking help for depression for a long time but Hailey knew he needed more."
Still, the source notes that these days, Justin is "far more in touch with his struggles."
"Between his motivation to seek more therapy and his goal to get healthy, his friends have faith he'll get through this," the source says.
A source previously told ET that Justin felt he "needed an emotional tuneup" and with the help of his wife, family and friends, was seeking help. The singer was candid about his issues in a recent joint Vogue interview with his wife.
"I got really depressed on tour,” he said of his Purpose tour in 2017, which he ended up cutting short. "I haven’t talked about this, and I’m still processing so much stuff that I haven’t talked about. I was lonely. I needed some time."
He also acknowledged he was coping in unhealthy ways and said he had a "legitimate problem with sex."
"Drugs put a screen between me and what I was doing. It got pretty dark,” he said. "I think there were times when my security was coming in late at night to check my pulse and see if I was still breathing. ... I found myself doing things that I was so ashamed of, being super-promiscuous and stuff, and I think I used Xanax because I was so ashamed. My mom always said treat women with respect. For me, that was always in my head while I was doing it, so I could never enjoy it.”
Watch the video below for more on Justin and Hailey.