Just last week he was saying he's not happy. He always said he needed "peace" and he said he hasn't found it yet.
So yes, it takes two to contribute to the demise of a M, that much is true. But until you start owning your half, you will get nowhere fast. And it seems a lot of these folks say they are unhappy and later realize (hopefully), it wasn't the M that made them unhappy, it was something within them.
My x had told me that he was unhappy for 5 years when I got the bomb - I had no idea. Since then, he has said that his affair partner-now fiance had replaced me in his heart, and that he is happy. In my case, I don't think it was within him, but within our marriage. I was just clueless.