OP. I've RTWT and i think you are awesome. That feeling of peace, autonomy and not having his moods and behaviour to deal with everyday is priceless. You will realise how much energy you used to spend all day thinking of him and his needs, how to placate him, avoid arguments, tiptoe round him, etc and you will sadly realise how the kids inevitably learned to do this too.
You also don't need to justify leaving to anyone. He doesn't make me happy is a good catchall, or we weren't good together, or simply I just want to be on my own with the kids. But mainly, whatever anyone else thinks is irrelevant and don't feel you need to explain.
His lack of responsibility is what is getting me. He thinks you should pay his fine, and the rent arrears, and for his coke and drink habit, and most of the household expenses? Fuck that. And he thinks he is going to get away with it in court and in his marriage. Stupid stupid man. He hasn't cured himself of his alcohol dependency, because he hasn't hit rock-bottom yet. He will go back to it, and like other PP I strongly suspect he has been drinking the whole past 3 weeks. Otherwise he couldn't have maintained this chipper exterior. He isn't doing any work on himself, and he won't change. He is lying to both himself and to you.
Hope you get out on 1st July and if you have any more wobbles, because you will as you are a good person and he will make you feel guilty, them post here and the amazing PP on this thread will set you right.
You may be able to tell that I speak from experience.