Bee,
First of all I want to tell you how great it is that you are so open to listening to and asking for advice. I wish I had've had the strength to reach out for help a lot sooner than I did. So, good on you!
You asked where I learned about boundaries. I learned about constructing boundaries instead of trying to enforce rules right here on SoberRecovery (search button at the top of the page > advanced search> thread title only > "boundaries"....you will see hundreds of threads in Friends and Family as well as others) AND in a book called " Codependent No More" by Melody Beattie. I STRONGLY suggest you buy,borrow or download a copy. That book changed my life and saved my sanity. It's kind of a bible for us codependent types. Seriously.
As I said, I started out with the " I will not engage with him when he is drunk" boundary and evolved to the "will not live with active alcoholism in my life" boundary.
I also had,
-I, nor my children will not ride with an intoxicated driver.
-I will not buy alcohol nor pay for alcohol for an alcoholic.
-I will not sleep in the same bed with a drunk alcoholic (even if that means the couch for me)
-If I feel uncomfortable I will remove myself from the situation (even if that means going to a hotel)
-I will no longer allow myself to be manipulated through guilt tactics
-I will not let other people's fear or resentments keep my from educating myself about addiction and codependence
When you start setting boundaries your life changes in ways I'm not sure how to put in to words. You get your power back. Really, the only person we truly have control over in this life is ourselves. I don't even think about my boundaries any more... they are just there and I don't allow them to be breached. I don't tolerate, liars, thieves, active addicts of any kind or disrespectful people in my space. It just is what it is, and it's a much more peaceful way to live my life. I've lost friends and family because of it, but I'm ok with that. I don't think my boundaries are in any way wrong or extreme. Even if they were, this is my one life and I get to choose how to live it. I can't force anyone else to live the way I think they should, but I damn sure can set boundaries that allow me to live my best life, my way.
Best of luck Bee, keep coming back. Keep reaching out and asking the tough questions.