You are not selfish, you have to do whats right for yourself at the time. You are married you haven’t just walked out without trying to help over the years. Like Danny says you have to admit you have an addiction not just a problem.
I’m in a similar situation (if you read the other stories) my husband hasn’t even admitted he has a problem with the cocaine never mind addicted to the stuff. But alcohol is the trigger in our case, he has a drink with his mates then out comes the coke. But then again if you are craving it you’re gonna take it anyway. I’m fighting a loosing battle too, you are not alone here and no one will judge you leaving.