Should also note, we live in a wonderful time where there is a wealth of materials out there for the curious to wallow in, lots of it free. Youtube channels like Numberphile are wonderful. I'm addicted to AoPS (Art of Problem Solving), which is math by mathies for mathies, all for the love of math. There's lots of great threads on these kinds of resources.

When school taught my math monster not only to hate math, but eventually also to believe that he was no good at it, I finally had to put my foot down. I try hard not to undermine his school, but in this case I explained point blank that that stuff he did at school wasn't math, THIS was math and this is something he has always loved. It took a couple of years for him to come back fully, but now he's back to begging daily for more math.