In a deeply personal interview, Martinez, who has endured a series of injury setbacks since joining United in 2022, admitted that his mental health took a hit during his time in the Netherlands, which has continued at United.
The Argentina defender is currently recovering from an anterior cruciate ligament but had time to sit down with Clank Media and Argentinian journalist Juan Pablo Varsky to speak about his mental health and how has been suffering during his career.
Therapy has helped
"I've been in therapy since I was at Ajax," Martinez said.
"I was always against it until I found myself at a point in my life in Amsterdam where I had everything.
"I played for a European team, I was in the national team, I had the car I always wanted, I played every weekend, and I still felt empty, like I wasn't happy.
"It's not an easy process. You have to have the humility to accept being a normal person. Yes, I'm a footballer, but it's a profession, it's a sport, and we're all people."
Amorim is changing United for the better
However, Martinez says he has a good relationship with new head coach Ruben Amorim, who he thinks has brought "energy and willingness" to the squad since his arrival last year as the club continues to evolve.
"The club is obviously going through a process of change," he said. "Since Six Alex Ferguson's departure, they haven't found a manager who hits the right note. Ten Hag did a remarkable job at Ajax, which is why he went to United, and thanks to him, I joined the club as well.
"It's like everything in life: you take a gamble, and sometimes it works out well, sometimes it doesn't. I think that, like any club, if something isn't working, it needs to be changed. It's necessary to analyse what's working and what isn't and make changes accordingly because that's how great clubs operate. Manchester is one of the best clubs in the world.
"Now Ruben Amorim has arrived with very good energy and willingness. I believe he will make the necessary changes. Without a doubt change is needed, because where we ended up in the table over the last two seasons is unacceptable."
Despite setbacks from injuries, Martinez has persistently proven that he is one of the best defenders in the league, despite many writing him off due to his height. Amorim will be happy to welcome him back to the starting eleven once he is fully fit as they prepare for their preseason, which starts later this month.