TW: suicide
Sorry for the long post, but I can relate to some of this, so I'm giving my 2¢ and advice.
Just reading this has me sooo pissed off.
First, I'm so very sorry you're going through this. You deserve so much better, you deserve peace. Especially after 8 fucking years.
Second. Idk how you do it, I know I couldn't for 8 years. I nearly quit after 2-3. I know many would say, "leave his ass!" and honestly, 8 years of misery would justify you leaving, imo. However, I understand love will make us do things we normally wouldn't. You love this person, you put in so many years together, kids, house, etc. I get it. But I will say, kudos to you for being so strong and dealing with this nightmare. You're a hell of a tough cookie. I will also say that don't neglect or forget your self-love, because without it, you become a shell of yourself and take shit that you shouldn't.
Third. This is the part that made me see red. I want you to know that you're not his mom. You don't have to hold him responsible for anything, and I mean anything. If he doesn't want to recover and/or take it seriously, then let that happen. He will eventually lose you if he doesn't get his shit straight. Maybe then he'll get a clue. Another thing is the comment, "THIS IS WHY MEN RELAPSE!" Idk if you said anything, but my response would be, "AND THIS WHY WOMEN LEAVE OR KILL THEMSELVES!" I'm sorry, but that's genuinely what I would shout back. As for the lack of empathy, especially the giggling and whistling - I can't stand that shit. I honestly don't know how you haven't slapped him. I would have to fight the urge to backhand or punch him when he did that, then follow up with, "you better get a fucking grip or the next thing I'm hitting you with is divorce papers!". You're supposed to be gentle and walk on eggshells around him but he gets to be a heartless, cold bastard to you? Nope, not okay at all.
All I can say it, don't kill yourself over this. Don't become a shell of shadow of who you are. Don't let your life be completely ruined by this. You deserve peace, love, loyalty, and respect...he and his addiction seem to be none of that.
TL:DR you deserve better, especially if he isn't willing to change.