I don’t think you should feel stupid at all for allowing the contact, we can only learn as we go along, in often the most adverse of circumstances. There is nothing stupid about trying to make sense of what we later see as the senseless.
Hopeful if you are stupid, then you are not on your own, I would be right up there with you, going on the amount of times that I allowed the addiction, its lies and manipulation to re enter my life, only days/weeks later to discover that it was of course exactly the same and often worse.
I used to get these horrible gut feelings that I was being spun a yarn but at the same time wanted to believe that this time it would be all true.
Every time I believed I seemed to become a little more vulnerable until I had long enough too see it for what it actually was.
It is a painful fact to face that what is being said is just a cruel act of manipulation. It is much harder to know that love exists but cannot be because addiction has planted itself well and truly in the middle. Your CG may well love you it may not be all a complete lie but none the less he is gripped by something that kills off feelings on both sides until eventually it is just too late and the damage is horrendous
You will have done all you can have done to point him in the right direction and to have supported him should he have wanted to change, probably like most of us having done way too much than what was good for you and probably him to.
You’ve been through a hell of a lot and made some very tough decisions and after all of that he maintains there is no problem ! I think that says it all really.
I think the good thing is that now you are going forward, you know and can recognise the tactics and as hurtful as it is, you know the level of manipulation that is going on and that knowledge will stand you in good stead in the coming weeks.
Please don’t put yourself down for falling for it or not always being strong enough not to get sucked in, we’ve all been there.
Keep posting, keep blocking !! and you will get stronger and your more vulnerable moments will get less, concentrate on you and what is good for you, enjoy the company of others that do not want to take from you and who make you feel good about yourself, it goes a long way