JS,
Welcome to SR. You've found a great source of support in the good people here. They understand what you are going through, so make yourself at home.
You said it best, "You do not want to live like this the rest of your life." You are also very smart in seeing that the changes need to be made in you, not just the addict. And besides, I know couples where the addict got sober/clean and they were still (the couple) just as miserable. That's the problem....we think if the drinking and drugging go away, we'll have this fairytale relationship. WRONG!
I'd recommend finding some Al Anon or Nar Anon meetings in your area. I can't stress how much they have helped me. I found that by going to those meetings and following the 12 step program, I HAVE been able to change the way I think, therefore changing my behavior. And those things are key to who I allow and don't allow in my life. So, if you want to change yourself so you'll stop this pattern of picking addicted men, meetings would be a great place to start.
And JS, it is NEVER too late to start over. I know this sounds so easy for me to say, but it isn't. But I KNOW, JS...I KNOW because at middle age I have changed myself and my life by working a 12 step program. Now ask me would I go back to the old way I used to live. NEVER. I pray I NEVER have to go back to that life of stinkin' thinkin'.
I pray you'll find some meetings and go and continue to go. And in the meantime, just ask you HP to help you through this. He will because He is in control.
Hugs and prayers,
Hangin' In