When we are young - we can look the other way A LOT. And we can look back and consider ourselves stupid but only with time and maturity can we "get it". My ex drove drunk a lot. He was a guy who got drunk on 2 beers.
Just after I had Ryan (firstborn), he and his buddies went golfing. Hours and hours later (when he didn't come home), I found out he had got blitzed (he told me he and his buddy were drowning their sorrows over becoming dads - WTF??? Our baby was PLANNED). He left the parking lot, hit a sign and did damage to the car that night. (the first of many such incidents). But our neighbour cop went and got him. I read him the Riot Act that night and then began the routine of him screwing up and me freaking out and him begging forgiveness. The whole puppy with his tail between his legs syndrome. The thing is - his brain was also between his legs. Making good choices was NEVER his forte. But I think "I" was the stupid one. It was so ingrained in me by my parents NEVER to get divorced that I continued to take him back and put up with his crap over and over again.