He didn't say. He just text messaged me last Thursday, and I quote:
"I'm leaving. I don't want us anymore. It's over. Take care of yourself. I wish you well." And then he didn't text anything else. I was so angry that I didn't contact him until yesterday, when I tried to call him about some stuff I wanted back, and to tell him that I still hope he gets assessed for his longterm wellbeing and that he would always have a friend in me to support his recovery. I feel really bad mostly because I didn't know he was that immature to resort to doing that. I don't think he's with his ex though, they're just friends. His ex really doesn't like me though haha!