Yup, I am there as well. Gosh, how embarrassed I am by how many times I have posted that I have kicked the abf out of my life and how many times I have turned around a day later and posted he is back. yo-yoing through a relationship.
sometimes I think that my abf and I are just out of sinc, his worst times hit him exactly when my pms hits me, or we both get bad news at the same time, so neither or us are ever really able to be supportive of the other and we both go and cope with it in our ways -- his is drugs, mine is anger and temper tantrums and sobbing into my pillow.
I am hoping this time I can really stick to my guns, I have ended the relationship.
I think the thing is, when you are in a relationship with someone and you just end up not liking that person, it is easy to get out. hey, I didn't like, didn't desire my ex husband, it was easy to split up. but this situation, I love the addict, I desire the addict, and he has this problem , drugs, drink, and from my perspective it seems so obvious, he gets rid of the drugs and drink, and BINGO, we have each other to love. That's what makes it so hard, you are breaking up with a person you WANT to be with, you are breaking up with them because of a behavior which you can clearly see they should just stop.
All I can say is, don't beat yourself up for loving someone and wanting the best for them, instead use your energy to do the best for yourself, for loving yourself.