The 'Story of My Life' hitmakers split three years ago, and the 26-year-old singer - who admitted the band were "overworked" - revealed he lost track of his interests outside of that world.
Speaking on Jessie Ware's 'Table Manners' podcast, he said: "We were definitely overworked. I had no personal life, I learnt nothing about myself.
"I remember getting to therapy and the guy was like, 'What do you like to do?' I haven't got a clue.
"I just lived so long as this reclusive pop star who was afraid of people, who just stayed inside all the time. I needed to stop, definitely. It would have killed me."
Liam also revealed how the pressures of such a high profile relationship with ex-girlfriend Cheryl - with whom he shares two-year-old son Bear - put a strain on them as a couple.
He added: "I think we kind of rubbed off on each other a little bit in that way. In a bad way, actually. All of that stuff puts so much pressure on a relationship.
"For her, if you were going out somewhere, it would take so long to get out of the door because you're just so worried."
Meanwhile, Liam recently made his red carpet debut with new flame Maya Henry at a launch event for Rita Ora's Escada collaboration at Paris Fashion Week.
He said at the time: "[Maya's] awesome ... it's kind of got to the point with my life, where I'm like, screw this. It's not worth my happiness. If someone is going to take a picture, someone is going to do something. The difference is with her, she's so relaxed that it helps me relax in a situation ...
"It's been quite nice just going out. I've managed to explore a lot more of London than I ever have actually my life, which has been quite fun.
"My life has been quite normal recently, which has been a break. It's good. I'm enjoying myself right now."