You have not tired me at all with your thoughts. Ive been through everything you are thinking. I know all those thoughts.
I totally understand that even after reading on here various opinions & possibly even totally agreeing with those opinions, one can still be confused & struggle to cope with the situation. I get it. If this was all easy to do - we would all be fine & there would be no need for this forum. There would not be thousands of individual stories posted here. Unfortunately this is not an easy situation.
I did the same with my addict as you are doing now. I tried to rationalize her crazy addict behavior telling myself its not all that bad is it. I was clearly in denial. It took a lot of time for me to understand & break free from my own denial.
You wrote above "But I could see no efforts of him stopping. He just threw away the weed every time we fought and then the next day bought another stash. It was a compulsion! (If he hadn't met me though, I believe that he would continue using till the end of his days. He didn't feel that his use was problematic, he found nothing inherently bad about it, he said that everyone did it.)"
So if he hadnt met you he would still be using till the end of his days. Our addicts dont stop because of us. They arent using drugs either because of us. They are using drugs because they have various unresolved mental issues which have nothing to do with us. Because of that they arent going to stop because of us. They might slow down and / or promise the world but in the end they are addicts & are thereby driven to use various drugs. For us non-addicts its hard to understand this extreme need to get & stay high.
You also wrote: He didn't feel that his use was problematic, he found nothing inherently bad about it, he said that everyone did it. These are typical addict statements.
He doesnt have a problem. He doesnt think any of this is a problem. There is nothing inherently bad about it. Everyone does it. - Everyone does it I dont do you? You are the one with the problem not him. Same as me - she didnt have a problem I had the problem. Our addicts dont recover or stop abusing drugs until they fully recognize they have a major problem going on & actively choose to get structured professional help.
If you go back with him the only way it will work is for you to totally accept that he is an addict & he will use drugs. Other wise you are most likely in for a very rough ride. Add in to your thoughts marriage, children, house, cars loans for business, & all other typical financial responsibilities, etc etc things can become extremely complicated. Having a problem with his drug use given all of that in place will be way more mind blowing than the relatively clean & simple situation you are dealing with now.
As I said before this is your life. You have to do what you have to do. Make informed / intelligent choices.