Karisma
Welcome! My RAH also didn't drink every day, week or even every month - but when he did - watch out! I was like you, we met when we were young and I figured "it's a stage, he'll settle once we're married" One thing I quickly learnt was that Alcoholism doesn't get better, it gets worse. Luckily at this point we don't have children (although I kept thinking that maybe he would change then), and on Christmas day I had to call the police on him because it had escalated to a point I never thought it would - he shoved me, ripped my jacket and broke both my laptop and my glasses. When RAH woke up in jail the next morning, it was the biggest wake up call ever. He's now in AA and will have 90 days sober Mar 26.
For him, that was his bottom. However, for his mom, she lost her job, her friends and her house and she still continues to drink.
You ask "Can he change?" Yup, he sure can....the question you need to ask is "Does he want to?" If he doesn't nothing you do or say will make him.
I agree with the others about setting boundries - hopefully he'll stick to them.
I also didn't think my RAH was an alcoholic either because he never drank everyday, but that's like saying someone's not allergic to nuts because they don't eat them every day -they're still allergic, just like an alcoholic who doesn't drink everday is still an alcoholic.
Good luck and keep posting!