Welcome, Hailee. I'm so sorry you're going through this but I'm really glad you found SR.
You sound like you're doing a great job setting boundaries with the alcoholic in your life. Deep breaths, one day at a time living, and Alanon meetings (along with being here) have been essential to me. As for the anger, well...I echo tjp's comment about blameshifting. It's much easier to blame you than it is to look at what his relationship with alcohol is costing him, on all fronts.
Oh, and as for feeling like you "should have known" about the alcoholism because you're an RN, please remember to be gentle with yourself. Our professional knowledge does not protect us in recognizing red flags in our private/personal lives. If that were the case, I wouldn't be here either, and I'm sure many others fall into that category, too. Our personal lives come with certain "blind spots", so to speak. Be kind to yourself, you couldn't have known, and in fact it sounds like even his family worked hard to hide the realities from you. You could be the most amazing nurse in the world and still not have caught on to what was happening!!! One truly has nothing to do with the other. What I have discovered for myself is that I'm learning these things now, however, and applying that knowledge to my life in ways that I couldn't have done before. So it's a positive, though sometimes painful, process.
Keep your chin up, keep loving those babies and keep coming back. There's lots of support here.
Big hugs, and welcome~
posie