Ok, so... you have a fiance so I'm assuming you're a grown woman right? But... you want to tell your parents? This just doesn't make much sense. Here's what you do: change barns. Simple as that. If you leave, he's not going to follow you. Crazy, right?
If you're underage and saying 'fiance' because you think it's cooler than 'boyfriend', then tell your parents and then switch barns. There really are other barns out there, believe me.
And I have another idea: avoid the pervert. What a notion! Don't intentionally go by him! If you know he's a creeper, avoid him.