Something clicked in his head recently which made him pursue things in an individual, unilateral way. In his mind (and I emphasize this), he probably felt justified for the stupid moves he's making. I know the feeling. I've had moments too where I feel like asserting my individuality to the detriment of the "us".
If I thought my marriage had some uncertainty in it, and I wasn't 100% into it anymore, I too would pursue the high-paying job. It's a calculated move - "If my marriage falls apart, at least I'm captain big-shot" versus "I'm going to turn down an opportunity to be a big-shot in favor of my sketchy marriage...where, if the marriage falls apart, I'm going to be a 2-time loser". It all comes down to his willingness to fight for the R. I'll be honest...I personally don't have much fight left in me but thankfully we seem to be maintaining enough airspeed to stay aloft. I'm glad a huge opportunity hasn't presented itself to me right now because I would probably take it too. Yes..I'm a f'in bastard too.
He's operating like he's separated / divorced from you. You have a couple options. You can do what my W did years ago and "go silent" but continue to pretend to be the happy W and wait for him to get a clue. Eventually, when his career stabilizes, he will miss the "happy homelife" and start be focused on you guys. My W made life so comfortable for me during the past 9 years, that I didn't really think about leaving her and now I'm completely focused on the R and respecting her etc. Sure it's been a rocky start but we're setting a great example for our D6 now. I guess the other way to handle it is more confrontational. I'm not sure if he would simply retreat into his job or not. He's probably going to do whatever he wants at this point. He probably has a bit of the hyper-focus/compulsiveness problem that I have where he doesn't look at the clock, is 110% engaged on whatever is in front of him at a given time, makes unilateral decisions because "in the moment" with his boss.
Not sure if this helps anything. I'm sorry that things really suck for you right now. You might ought to save the energy you expend here in your posts to confront this issue with your H. Doesn't he read these though?
Anywhere is walking distance if you have the time
-Steven Wright