Veronica,
I so relate to where you are at.
I have children though, and have been dealing with the A for about 10 years now. Have been married for 14, so it wasn't always like this. But I don't remember when it was any other way.
I can't really give you any advice on weather to leave or stay, because that still plays in my mind all of the time. I to was raised where divorce wasn't an option. We have been seperated twice over the years, and he has always changed and relapsed. It is a struggle every day to hold onto myself, sometimes I feel like there is nothing left to give, he has taken every thing. I started coming here not to long ago also, and it has helped me so much to gain perspective again, and to realize that I am not alone, much stronger then I thought, and that no matter how down my relationship seems, there is so much hope for me and my children, and if my A doesn't want to be a part of that new hope there is nothing I can do. I have to take care of me first, I can't help or take care of someone that doesn't want that for themselves.
I have been reaching a critical stage in my recovery also, to make some sort of change. Not sure what change that will be, but something has got to give. When the time is right for each of us I believe we will truly know what to do and what is right for ourselves.
My prayers are with you.
I think you are very wise to sort out your options and make some lasting decisions before children enter the picture. After children become a part of the decisions you have to make it becomes twice as hard, because you have so much to risk.
I wish you well.