Maybe I have been lucky, and my experience is atypical. So please consider that when reading.
My ADD spouse never stood me up. He’s texted me if there were issues–bus breakdowns, migraines, and all that. He was legitimately, and is legitimately, an honest and caring person. And sure, once or twice he did just space things. But he would remember and communicate with me. We’d reschedule. I would make our plans flexible, and have a backup activity for if it were “just me”.
You mentioned your date abuses alcohol and Xanax as well as marijuana. He’s got no job, and no place he really lives. He won’t text you or show up on dates.
I don’t think the behaviour you’re describing is “just ADD”. It honestly sounds like serious substance abuse.
Common behavioural traits of a substance abuser:
1. They LIE. (Often continually.)
2. They manipulate.
3. They’re likely to engage in criminal acts to feed their addiction.
4. Blame shifting – usually onto their romantic partner or other caretaker.
5. Abusive behaviours – again, usually onto their romantic partner or other caretaker.
You can’t change an addict or addict’s behavior, no matter how hard you try.
You can’t rescue them. (Codependency is a real trap.)
It’s definitely up to you to do what’s best for you. I don’t know what that is, but I trust that deep down you do.