It's good that you admit you've got a problem and that you're taking action. Just remember, you aren't the only person who has ever messed up your marriage [because of addiction]. I did it, too.
You can get to the other side of this situation. Things may not work out the way you hope, but this situation will pass. Yes, right now it is horrible and you feel horrible, but you can survive.
No matter what horror we bring upon ourselves, surviving it is (usually) possible with a little work and perseverance. As long as you're ready to change, you're making a step in the right direction.