I don't know what's hurting you the most, his behavior or the fact that people in your family have not told you this stuff earlier.
As far as he goes -- alcoholics lie. They lie and drink. Drink and lie. That part, while hurtful, is not really a surprise.
As far as the family goes -- I can tell you about mine. My family knew I was married to an abusive alcoholic. Even though we don't live in the same state and only see each other at holidays, they knew. I went through a phase where I was pissed off that they hadn't done anything. And then I realized that if they had told me before I was ready to hear it, I would have broken off contact with them. And they were afraid of that. So they played nice until I was ready to leave.
I am so sorry you are hurting. And let me just tell you that even though it feels impossible right now, you will get to a place in your recovery where you are standing firmly enough on the ground that trusting someone else isn't scary anymore. Because if they prove to be not trustworthy, you're still standing. In your own strength.