Your #1 priority is to keep those boys safe --- physically, emotionally, mentally, spiritually.
I separated from my husband of 16 years about 11 months ago. My husband has been drinking alcoholically for about 8 years, he's one of those 'functioning' alcoholics who drinks in secret and everybody thought we were the perfect couple/family. We have four kids, ages 11, 14, 17 and 18. I swear, they were so little just yesterday. It was the hardest thing I've ever done, to initiate separating our family. The day I asked my husband to leave, I felt like I was standing at this precipice, knowing I was going to change my kids' lives forever. They weren't even totally aware that dad was an alcoholic, but his behavior was confusing for them and very very stressful for all of us. And I was very troubled that they (2 girls, 2 boys) were learning extremely toxic patterns of relating. It just got so that one day I could not take it anymore.
I love my husband so much and for all the Al Anon work in detachment, etc it still pains me exquisitely to see him choose this life. BUT I could not in good conscience, as a responsible, decent mother who took on the immense responsibility of PROTECTING the children I brought into this world, continue to expose them to his shenanigans. Don't feel bad about leaving ---- feel bad about staying. Your boys are so young, you have a chance to move on and they won't remember much now. Wait a few years and it will be far more complicated, more damaging to them to leave their dad, and you will be all the more beat down. Don't be afraid to stand up for what's right, and make it happen.