"I was supposed to go to school and college for baseball," Wahler revealed. "Everything transitioned [after the show] ... There were a lot of things that came overnight that were very, very glamorous ... and that's when that downward spiral [happened] for me."
"[The fame] ignited my addiction and things started to domino effect right before my own eyes," he recounted. "Before you knew it, it got out of control and I couldn't handle it."
Wahler, who was often seen arguing with Conrad on the series, admitted he became "a totally different person" while using drugs and alcohol.
His substance abuse led to a suicide attempt in 2009 after multiple arrests and stints in rehab.
"My addiction drove me to suicide," the star said. "Not contemplation -- actually attempting suicide -- and somebody found me and that's why I'm still here today. I'm very grateful for that."
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Wahler has been sober since 2010 and opened the sober living facility Widespread Recovery in Orange County, Calif., in August. He and wife Ashley Sack married in 2013 and plan to start a family soon.
"It's not hard to get sober. The hard point is staying sober," Wahler told The Fix while discussing Widespread Recovery in September. "We want to give people the tools so that they'll be able to succeed and prosper."
Conrad, meanwhile, has launched a number of fashion lines, including Paper Crown and LC Lauren Conrad, since her time on "The Hills."
The 30-year-old designer teased a new project with MTV in an Instagram post Wednesday.
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