Napoleana, you seem to be asking a few different questions. I guess you want the answer to be "Yes, you can fix it all & live happily ever after" ... I'll try and answer the ones where I might be able to give you some insights and, hopefully, trigger your view to a way forward.
Firstly: Is an addict always an addict (to something)? Yes, we are. I'm an alcoholic but I manage my drinking. However, yesterday I ran out of tobacco and had no money. I was not only suicidal & completely incapable of doing anything constructive, I even considered begging for a fag (that would not have been a pretty sight.) I've been like that, at other times, when I had no access to chocolate, coffee, or cake! It's a perfectly crap part of my personality - I know how I got this way, I've done 10 years of therapy - and I can't shift it. The ~Anonymous fellowships work by replacing the problem addiction with an addiction to recovery; it's still the most effective method of treatment.
Secondly: Are the addictive behaviours more important to him than me, or our children? It's probably a huge internal issue for him, but the answer is yes, if important means urgent. Sorry :(
Thirdly: Do we mean more to him than his addictive behaviours? I imagine he could - perhaps does - agonise about this in depth and detail. The truth is, and addict also does relationships addictively. If you were to remove yourself and your children from him, he'd feel desparate withdrawal. He would lose this pain in other addictive behaviours. That's probably all you need to be told.
Last and hardest: Can I get him to recognise his priorities? This depends on him and how far he's able to go. What's certain is that you can't achieve this by giving him space. You might be able to do it by pushing him to make choices - and that means pushing hard. Call time. Let him know there's no "everything" any more. Tell him you'll support him MINIMALLY while he figures himself out, you'll attend his family counselling sessions if/when he gets that far, but the third parties (substances, behaviours, self-indulgences) have to go. And that he can't have his family while he has them and they have him.
Alternatively, you could decide to live with it all on certain terms. You sound fairly happy in general and I don't know whether that's just your presentation (the picture you paint for yourself) or pretty much the way things are. If your problem is mainly about coming 2nd or 3rd in his life than 1st, then can you find some rules and sanctions that work for you & DCs? If you go ahead and plan your lives without his expected presence, will that work for you? It will for him.