Amy - I am sorry and I so understand. It's good you held onto those texts preceeding BD to be able to see the reality.
Unfortunately, there is nothing you or anyone else could have done to stop this. In between my BD 1 and BD 2 I DID try everything. I pretzeled myself every which way thinking we could fix this together. But no matter how "perfect" I made things, he was still unhappy and I was exhausting myself. Work was a break from working on my marriage. No joke!!
You cannot save someone out of depression until they see they are in it. It is that simple and yet that complex.
I am betting if you really think about it, you'll realize your h was irritable and angry 2 years prior to BD. And have you seen the shark/dead eyes? I went back to old photos and was horrified to see my h had the dead eyes in every photo starting sometime in 2012; he bombed me in 2014 and the eyes are still dead in every photo. He used to have such a glimmer.
The changes are sooo subtle, that maybe you caught he was off. But I predict that anything you "tried" just made him more cranky. And therapy would not have worked because they don't believe it's them so they won't even go. They think the answer is a condo in the city and a Corvette!!! He has to go through replay. He has try everything assuming the next thing will make him feel better/make him happy. I have watched it all go on before my very own eyes. It's really amazing to witness.
Use that anger to move you forward. Get it out however you can: yoga, working out, walking, etc.
You did not cause this. Well adjusted, balanced people do not become the opposite of who they were 2 - 3 years ago. And yet every MLCer does this.
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