Future tripping with husband

You and I are blowing my own mind at the moment!
I have had a problem with my husband’s level of drinking for going on maybe 8 years… a long time. Recently I’ve kind of given up on worrying about it – a hard habit to break after so many years, but I’ve come to realise it has nothing to do with me and has no negative consequences for me other than occasionally disrupting my sleep, which he is aware of and tries to temper.
I am now pregnant with our first child but my mind is jumping to when the baby is born and if he’ll be able to cut down the drinking. He says he plans to but I’m concerned it won’t be that easy after so many years. Should I just trust and leave it in the future? I clearly can’t set a boundary around something that hasn’t happened yet!