Chrysene......I have a question...for the sake of discussion. Why do you have to get married? What would happen, if you didn't?
From what you shared...it doesn't sound like you have a bun in the oven...lol...and it doesn't sound like your dad has a shotgun...
And, you are capable of earning your own good living....and, you don't need him for status, etc...…
It is not like the sound of a biologic clock is ringing in your ears.....
Why can't you continue to share life with him...and see how it goes for the nest few years....As you know, if you have been studying your materials on alcoholism...that it takes a couple of years...or even more...like 3,4, 5...depending on who you are talking to...to see if the life style of total abstainence really takes hold.....
He will never be cured, of course....he will have to commit to the program and principles and the heavy lifting that it requires...for the rest of his life....
It is a lot easier to protect yourself by walking away if that piece of paper, and all that it entails, hanging over your head......