'The Rockstar' is gearing up to face Peter Wright in his opening match of the Players Championship Finals as the late-year calendar ramps up.
Cullen is the current world number 32 and has two titles under his belt this year, with more on his radar before the next month's season-ending World Darts Championship.
Yet despite that success, the 36-year-old concedes he has lost part of his spark for playing darts, which has affected his motivation.
"I've had a tough couple of years, on the board and away from darts," Cullen told Online Darts in a candid interview.
"I'm in this predicament now because of me. It's not your fault or anyone else's fault. There's only me that could put it right.
"I think the last few years, I've lost a lot of love for the game. I don't enjoy playing darts anymore as much as I should.
"There were times when I used to look forward to playing darts, but now, I look forward to having the craic with the lads more. I think I'd miss that more than the darts. And that's not right."
When quizzed on how he could rekindle his love for the sport again, Cullen referenced how the likes of Luke Littler and breakthrough Dutchman Wessel Nijman have that extra bit of hunger to compete.
"I think the problem I've got at the minute is, there are so many more players that I don't think have as much ability as I have, but they're so much more hungry than I am. And that counters it," Cullen said.
"If I'm not essentially too bothered by what the outcome is, somebody with less ability – who absolutely lives for darts – has a better chance of beating me.
"You look at people coming through like Wessel Nijman, who's playing unbelievable darts, and you can tell he loves the game. The way people talk about the game, the way they talk about the equipment – they love it. And I just think, well, I can't remember the last time I felt like that."
With key matches and tournaments coming up in quick succession, Cullen feels he needs to find the right balance of competition to rekindle a "dormant" fire inside him.
"(The fire is) not gone, it's more… dormant. In the World Championship match against Wessel, I suddenly felt it again. But you can't force that in every match.
"I need to find some sort of middle ground. I used to be good on the floor and bad on TV, then it swapped. Now I need to get both back."