My husband had a difficult time coming off cannabis. Twice in fact. It never used to be a problem but then he ended up under a lot of stress and soon started using it all day, every day. He quit after I told him it was me and the kids, or the weed. I did this because it was dragging him down and because it was dragging us all down in the end, especially financially. I couldn't even afford to do the shopping. He quit that very day and it was very hard for him, but like yourself, his kids were more important.
Unfortunately a year later after not touching it, we became even more stressed when the previous situation rose its ugly head again and someone offered him some so he gave in. He said it was only going to be occasional but of course it was a slippery slope.
At the time, he was going through court for access to his son, so I told him he had to quit because how did he know his ex wouldn't demand a drugs test and that could be him screwed. Eventually, he gave up and hasn't touched it since.
It's really not easy, especially when life becomes stressful!
You've done very very well