If this is changing WHO he is and how he acts, YES I would be quite worried. Anything that changes a person, whether it's illegal or not, is dangerous and I would think twice if he's refusing to stop using it. Would you want to live with this person 24/7 the way he is now? I doubt it. You may want to rethink your trip in November if he's not going to stop using this "drug." And even if he does stop NOW, is he going to begin using it again after you marry? Chances are good. If he's using this to ease the pain of depression, you bet he's going to keep using it or begin again if he stops.

He needs to see a therapist, and soon. A psychiatrist would be best so that the doctor could give him medication, should it be warranted, and I suspect it would. Urge him to see someone, and if he won't, then once again I'd rethink my plans.

Best of luck and God bless -- and PLEASE -- let us know what happens? Hugs, Lee