Sex with a Professor (but not mine). Confused on what to do.

Okay, guys.First of all, I'm not sure if this is even the right place to post this, but i'm in need of some advice. Recently since coming home for the summer (college student), I met up with a cool dude, hooked up a few times, and we have become basically a friends with benefits. We're both discreet about our situations (work/family) so we haven't talked about anything too personal (ie: work). I recently decided on transferring colleges to the one in my hometown for several reasons (parents, cheaper, etc.), and while getting a tour from my friend, i noticed a picture of my FWB on the wall under a list of professors. Now that i know this, I'm sorta stuck on where to go. He doesn't know that I know and he also doesnt know that I'm transferring to the college he works at. I scanned the school's policy and it seems to me that he wouldnt lose his job because "relations" are only prohibited between a professor and his/her own students.So here's the question, do i come outright and tell him the next time we meet up and let him decide on what to do, or do I pretend like I don't know until the end of summer and then let it out then.TLDR; I have a FWB situation with a professor but not mine. I'm transferring to the school he happens to work at and I'm unsure on how to tell him this.EDIT: As an added piece of info: We would be in two completely different departments being that i am a STEM major and he teaches in a Liberal Arts.