HIW, You are so right about that! I have read your post & am sorry for your situation.
"Basically, he told me that he was unhappy, had been for a long time, and that it was time for him to be a little selfish. Get up whenever he wanted, go out etc. (thanks, now that we have two kids!!!). I have been doing my masters for the last three years and did not put the attention I should have on our marriage. "
We don't have kids but this part of your situation is similar to mine. I suspect, but not confirm an A. I think you have a great attitude & are doing everything right, just wanted to offer my support.
Your sitch sounds way more hopeful than mine - your H sounds pretty conflicted, mine seems very sure about wanting a D & has been putting the pressure on a lot lately. This have forced me to recognize the possible reasons for this, an A being the one I most often read about. Am trying to DB, GAL, detach & all that other good stuff but he keeps pounding away at this. Like Stronger, I have felt like throwing in the towel & often hear discouraging advice from friends & family who don't get why I dont' just agree to it. I wish you the best of luck in DBing & wanted to let you know your attitude & strength are an inspiration.