Hey figgy, glad your DH took it OK. It probably doesn't help that you were ready for an explosion and he's alright, so you feel rather flat. But give yourself a little time to think it over as a couple; there are always options if you feel the issues are insurmountable (depending on your views of course -there may not be). But given that you seemed pretty keen on no.2, I'm sure you'll start to feel the happiness.
TBH Oi, it sounds like when he's in a 'stressful' situation he tries to exert control over it, and his way is gambling. Given that he's not a habitual gambler, he doesn't sound 'addicted' as such...perhaps some talking therapy would be better than GA to see if he could get to the bottom of it (and would avoid God-bothering)?
Sorry you feel distanced from him though 
I think mopsy that xiao's approach is a good one; I did loads of the housework-y stuff, cooking from scratch and cleaning when on mat leave with DS, and the 'it's bread day!' attitude works!
Interesting that he's back in contact with you xiao and not your DP (or has he remained in contact with him seperately?) Sounds like an interesting family discussion to be had- and remember, after a blow up like that you can have a relationship with them, but it's entirely on your terms. You know you can walk away from them and it'll be their loss, so you have nothing to loose....