The heart wants what the heart wants...

My boyfriend gets so drunk sometimes that he blacks out and doesn’t remember what happened the night before. He is trying to control his drinking because I asked him to and he doing really well but once in a while, about every 2 months or so, he slips up and goes on a binge that can last 2 or 3 or even 4 days. This happened last weekend and he confessed to me that he woke up in the morning with a woman in his bed. He called me right away and he confessed to me what had happened and he swore he had no memory of how it happened. He is really sorry but where does that leave me? Is getting really drunk actually a good enough excuse to f**ck another person. We were talking about getting married and now I don’t know what to do. I am dealing with a lot of emotions and I am so sad and angry that he could have been so stupid that he might have destroyed our future together. Do you have any advice for me?