There were pressures that were getting to him, he felt as though, if he allowed things to continue in this fashion. He might end up happy.
The problem with happiness is that once you have it, it's something that you can lose. When you don't have the things that are actually worth real value in life. You can behave however you want, without fear of too much consequence.
As soon as something happens, or comes into your life that is actually worth giving a damn about, well, that's when your behavior actually starts to matter again. Because if you truly care about something in your life, even if it's just one small thing. That one small thing actually makes your life worth living. That thing, makes your life; a life.
So when he actually got something that he cared about, it wasn't until he got scared of losing that he started to act as if he didn't want it. That's how these things work. You enjoy it, you take it for granted. You get used to it. Then, you start to wonder what your life would be like without it. Maybe, the pressure of having your life matter gets to you a little too much.
The responsibilities. Accepting the fact that not only does what you do matter, but you can go back to it not mattering any time you choose, because you chose for this thing to be in your life.
It's easy to go back to what you were before, because what you were was rock bottom. It's always easy to fall, climbing takes practice, and a defiance towards gravity.
So you're forced to choose, the fall, or the climb.