Sorry to hear you are going through this. It sounds very similar to other addictions, my husband is like a completely different person when he takes cocaine or other drugs. He has done things I wouldn’t have thought he would do such as owe out all his wages, taking risks being on these substances while at work in a job he loves and he actually tried so hard to get this job but he would risk it because the addiction is so strong . It certainly is like another person but I guess that’s where he has to come to realisation that it isn’t another person- it is him who’s made those choice and if he wants to fix it I wouldn’t have thought it would be healthy to avoid the blame. I would think it would be hard to move past this if he genuinely thinks he doesn’t need to take any responsibility for his actions. Wishing you luck, will be thinking of you.
