Tfish - as everyone says of course you are not to blame. But maybe be careful on your response to it all. Your h also may be trying to get a reaction out of you so that when you two argue he has his "reason" why he is unhappy.
There was a period where my h did this. He would blame me for ridiculous things, I would counter him thinking I was setting the record straight but I soon realized that by engaging, this led to light arguing and I was keeping myself in his formula giving him a false target for his unhappiness.
Then Job taught me to say, calmly and quietly, "sorry you feel that way" and walk away. This way I did not engage with him so how could I be the cause of his unhappiness? Just a thought.
Sotto - laughing out loud at your h's immature MLC thought process.
Me 41, H 47, M 15 yrs, S11, S13 BD 1: 11/4/14 we work on it; really I pretzel myself BD 2: 3/31/15 H goes down to "dorm room" 8/15: H back to MBR 10/15: H back in dorm room 1/18: H files, now divorced