I think it even goes deeper than the alcohol. Lots of women want to be known as the one who "made the bad boy settle down." She's known you forever and therefore is pretty informed about your sexual history. She would be able to say, "yeah, he just fooled around with all of you other girls, but he loves ME enough to get married." There's just something about a confident, self-assured man that makes SOME women want to be the one. Hell, I'm attracted to you and I know nothing about you except that you KNOW you are hot and "good at what you do!"
Disclaimer before I get flamed - I am NOT saying that every woman on this board wants to tame a wild man. But an awful lot of ladies that I know do. It just depends on how they act on this attraction. I don't think I could ever admit to a man that I have known for years that we would be married unless it was our honeymoon. Feeling it and admitting it are two different things. No matter how much alcohol I've had.
Do you think she's hinting for a ring?