DH drunk while looking after LO!!!

I am just furious and feel lost.Left my lo -6 month old baby with DH for the evening and when called him to find out how they are-realised he was drunk .At first he did not want to admit it,after admitting starting accusing me of overreacting and being difficult last few months, and being miserable and that it is his "escape"!I know I was not my best last few months -have PND and am seeing a therapist at the moment,trying really hard to get myself back on track while not having any support (we don't have our families around and DH works full time),been tearful or angry quite a lot.But drinking!!!-I just feel I can't trust him anymore with lo..I think every time now I would need to go somewhere -he will do it again .He used to have a problem with alcohol before few years ago but it was all good for a while .Now all has got even more complicated -came back home ,saw him drunk ,lo not sleeping and crying ,DH trying to talk to me about how bad I am and shouting at me as I did not want to talk today ,looked at him and realised that I don't think I want to be with him anymore :(sad -not sure if its depression talking  or it's the decision to make :/scared as if that's what going to happen and we divorce -I will be in a hard situation both financially and emotionally ,but don't want the possible trouble to stop me from doing the right choice -and my priority is the little angel who is finally asleep .Any advice ?:-)Thanks