Marler was reflecting on the March 2016 incident where he insulted Wales' Samson Lee by calling him a "gypsy boy"
The 28-year-old, who has 59 England caps, was speaking as Harlequins joined the Movember Foundation to launch a ‘Be a Man of More Words’ campaign, raising awareness for World Suicide Prevention Day on September 10.
Marler was joined in a video by Quins team-mates Dave Ward, Danny Care and Mark Lambert in speaking openly about their personal experiences, with Marler reflecting on the March 2016 incident where he insulted Wales’ Samson Lee by calling him a “gypsy boy”.
“It hasn’t always been easy,” Marler said.
“My personality is I can be very outgoing, very happy, sociable, but then I can quite easily buckle under pressure, get quite low and spiral.
“I’m now in a place where I’m far more in control of my day-to-day outlook on things.
“A huge part of that was being able to talk to my friends. They’ve enabled me to be in a position now where I’m capable of coping with that.”
Marler apologised for the incident in England’s 25-21 win at Twickenham, while Lee’s interpretation was that the comments were intended as banter, rather than malicious.
The England prop was banned for two weeks and fined £20,000 after World Rugby intervened in a disciplinary case which had initially seen Marler cleared by a Six Nations panel.
The subsequent fallout and a further ban for kicking Grenoble hooker Arnaud Heguy in the head saw Marler opt out of the June 2016 tour to Australia with the blessing of England head coach Eddie Jones.
Marler responded by playing the best rugby of his career, earning a place on the 2017 British & Irish Lions tour to New Zealand, although he served eight weeks’ worth of bans last season, missing England’s first two Six Nations matches.
Marler added: “I spent a huge amount of that time discussing things with my wife, trying to get through that, but also my close friends around me about the problems I was experiencing at the time and how I was going to get through it and move forward.
“For me, without those guys that I was able to talk to, I wouldn’t have been able to get through those tough points in my career and in my life.”
Care spoke how fatherhood had changed him. The scrum-half was reprimanded by then England head coach Stuart Lancaster following his December 2011 arrest for a late night incident.
“Becoming a dad, for me just put everything in perspective,” Care said.
“Everything changed for me, my whole outlook on how I was as a person. I wasn’t a bad person, but I made a few bad decisions. For me the main realisation was someone is going to be dependent on me and I want to make that person proud and do best by my child.
“Now all my decisions I make I put my family first. That’s the biggest thing for me. Being a father you have to put other people first.”
The Movember Foundation, Harlequins Foundation and Harlequins join forces to ‘Stop Men Dying too Young’. For more information head to: www.movember.com