I desperately need advice!

My husband is a alcoholic, we have two wonderful boys (age 4 years and 7 months), I'm a stay at home mom and I'm not sure what to do. I am so tired of being lied to all the time, he's always promising he will stop but refuses to get any help. I have fallen out of love with him and feel a large amount of hate towards him for constantly choosing alcohol over his family. Not only does he turn into a crappy husband but he turns into a crappy dad too. I have told him I'm going to leave him and apparently that doesn't matter because he keeps drinking...I've been battling this for 2 years now. I know you're not suppose to give up on your spouse but when is enough enough? Anybody have any advice on how to deal with a alcoholic? I don't want to split up our family but isn't a broken home better then a unhappy home?