I think this is very personal information and he might not need to know that at this stage of relationship.....it's been just 6 months....
I'm not familiar with your condition, but I think it's not something that would harm him (like STD)....
Personally....I would have waited till I'm sure in my relationship and then I will tell....and if he's the one, he would accept your condition....
don't worry too much about it and stay cool about it....enjoy your relationship