Balance. Not to be flippant, and I also enjoy AB's work, but no one thing or set of things is never the answer to sustainable peace of mind.
Ironically, one thing that made AB's character so appealing was his balance of ex-junkie hardness and childlike wonder.
There's a great Velvet Underground song, I Found a Reason, with the lyric, 'Oh, I do believe / If you don't like things you leave / For some place you've never gone before.' That place isn't necessarily a 'place.' No one ever does everything. You will die with meat still left on the bone. Take comfort in that.
I was also depressed and addicted, then when I quit I met a woman who wasn't good for me. My feelings for her became another addiction. This article clarified for me the reason he killed himself. I can totally understand not wanting to go on living without the woman you love and need in a very intense way, and worse, a woman that torments you.
His death still worries me in a sense for my own life that I still want to do a ton with my life but I don't want to do quite everything. There needs to always be something to dream about, something needs to be left unfulfilled.
I can completely get for Bourdain that at the end there was no fix left. He had literally done everything in his life possible to do. What could he possibly dream about at the end? I am sure that is a much darker place then what it would seem on the surface. "Instead of killing myself, I can do anything so I should do X." He literally ran X dry.