Hi Soulful
The questions you are asking yourself are not unique. I have asked myself the same types of questions countless times.
The only answer which makes sense of it all is addiction. Your husband has been & is an active addict chasing powerful destructive drugs. Doesn't sound like he was doing coke here & there what sometimes is described a recreational use. . Sounds like a full blown addiction problem.
I took me quite some time concerning my relationship with an active addict to understand the many why's. That understanding came from reading about addiction. What I learned wasn't pleasant. However what I learned explained most all of it.
Addiction is progressive & destructive. Our addicts minds are severely altered & do not function in a rational manner. The chances are slim you will get answers from your addict. I never got answers from mine. I believe, based on my experience, your answers are out there to be found - but you will have to find them.
In my case, the search for those answers also helped me find myself.
I wish you the best.