Congrats on your newfound level of fun
Who would benefit from your telling him - you, him or both - and how? In the short-term or in the long run?
On one hand I agree with the previous posts, but if iyou don't tell him and it turns into something that's going to eat at you for years, that could affect you both in the long run as well.
Sorry for the wishy-washy non-answer...