Turns out, Morgan Spurlock, who directed the 1D movie, This Is Us, spent a lot of time with the guys and does has some insight into what Zayn might have been going through over the years. In his words, Zayn "struggled" with that level of fame and is really a "homebody."
Morgan told HuffPost Live: "He always struggled with being on the road. He's a homebody. He wanted nothing more than to sit in his house and spray paint and draw and do art, and I think this explosion that happened to him - which was something none of them ever predicted - but I think he was the one who struggled with it the most. And being away, being on the road, being away from his girlfriend I think finally just got to him, and I think he said, 'I'm done.'"
Morgan had fond memories of the now former One Direction star, even calling Zayn his fave (shhh, don't tell the others), explaining: "I love Zayn. Zayn is probably my favorite guy in the band. I thought he was amazing. He was a huge talent, probably the best singer in the group."