I would have no hesitation in leaving my DH if I found out he'd knowingly put my DDs life in jeapourdy by driving, drunk. Strolling in tiddled after a long lunch and picking someone up from nursery if one (not good) thing, but driving FFS, criminal as well as criminally stupid.
What's next, leaving the kids outside the pub while he gets pissed?
You cannot risk your child's life if you ever think this will happpen again. Kick the low life bastard out.