Hi, I'd like to help you with your question.
What you need to look for here is whether or not Brian is willing to get help and deal with his alcohol use and his treatment of you.
Does Brian acknowledge that he is an alcoholic? That is a very important first step. Once he can admit he abuses alcohol, he is no longer in denial and is most likely open to getting treatment. However, if he goes to treatment just to get you back, then he probably is not serious and will repeat his mistakes.
You may also want to talk to at therapist about what you have gone through with Brian and why you feel the need to go back after you leave. You may have some co dependency issues. Try talking with your doctor for a referral or if you attend church, your pastor can help. You can also search on line for a therapist at http://therapists.psychologytoday.com/rms/.
With the help of a therapist and alcohol treatment, the two of you could stay together and work on having a good marriage.
I hope this has helped you,Kate