you really arent alone...............I too know how you feel I never have been able to get it..............when things can be so good then bam he uses...............just shows it really isnt about US! hang in there................if you havent read codepend no more maybe think about giving it a try it really helped me
also now I've just finished a book called getting them sober.........( I just substituted clean for sober and it makes very perfect sense)
good luck hang in there