It sounds like you have reached a point where you are ready for some changes in the quality of life for yourself and your kiddos. Good for you! It's a real milestone in recovery.
A healthy boundary is a very useful tool. However, so is a hammer but not if you are trying to use it to saw a log in half. LOL!!! It is a hard thing to accept that most active alcoholics will not respect boundaries. It takes a rational, healthy human being to do that. A large part of my recovery has been recognizing that I have definite boundary issues. My first hurdle was that I didn't clearly understand what a boundary was...that it wasn't something I imposed on other people but rather on myself.
There is some great reading here about setting boundaries. It really helped me better understand what I was facing inside myself. Here's a great one:
http://www.soberrecovery.com/forums/...oundaries.html