Justin Bieber says he was ‘USED’ by Kourtney Kardashian when he was 21 and she was 36

In a Dec. 17 interview on syndicated radio program The Bert Show airing on Wednesday, the pop star fields a question about speculation he had a romantic relationship with the reality star. (A source told PEOPLE in December that Bieber, 21, scored a “huge ego boost from hooking up with Kourt,” 36, over the span of a “few months.”)

“I’m being used, man. What can I say?” Bieber says on the radio show, jokingly responding to a headline. That’s when host Bert Weiss asks, “Anything there?” Bieber replies, “Nah, we’ll leave it at that.”

Following a brief pause, the “Sorry” singer explains that he has nothing but love for Kardashian, who recently opened up about suffering from anxiety in the aftermath of her nine-year relationship with ex Scott Disick, 32. “No, no, but for real, she’s great,” Bieber says. “I’ve known [the family] for years.”

Bieber – who later showed PDA with longtime pal Hailey Baldwin, 19, on their cozy New Year’s vacation – also touches on life without ex Selena Gomez, 23.

When shown an Instagram Gomez shared featuring Christopher Mason, a model in her sexy “Hands to Myself” music video, Bieber replies, “What is she trying to do to my heart right now? I’m just kidding. She loves me. I love her, too, always. Who’s this guy? He’s a joke! This guy’s a chump. Nah, I guess he’s pretty handsome actually – I can’t even lie.”

The conversation soon takes a serious turn. “I just want her to be happy,” Bieber explains. “I love [Selena]. We’re friends still. We needed time to grow for ourselves and we were like, ‘Maybe we’ll come back together in the future,’ and then it ended up being so long and we just grew apart and we’re not the same people anymore.”

Bieber’s interview came nearly a month after the release of his new album Purpose, for which he worked around the clock to promote. According to Bieber, exhaustion is what pushed him to walk off stage during a performance in Norway. “I was just cranky,” he says of the incident.

I was just so exhausted and I felt like, ‘I came all the way out here to do a show for you guys and I’m asking you nicely, can you please just not pull on the towel?’ Regardless, it was a messed up situation, I overreacted. [People said], ‘Justin Bieber’s being a little bitch.’ And I was. I’ll be the first one to say it because I’m human and I have bad days.”

And even though he understands what went wrong, Bieber insists he’s never going to be perfect. “I’m still going to make mistakes,” he explains. “You might see me on TMZ tomorrow doing something dumb. But I think what’s cool about this growth is people can see it. I’ve made a transition and been consistent. Life is just about staying consistent and pushing forward. This day might suck but let me just look forward to tomorrow and better days to come in the future.”

As for what 2016 has in store, kicking an old habit to the curb is at the top of Bieber’s list. “My New Year’s resolution is to quit smoking,” he shares. “It’s not healthy and I don’t want to be someone who people are like, ‘Yo, he’s smoking – he’s a bad influence.’ It’s my journey, go live your journey. This is my vice right now. Let me be, I’ll figure it out.”