I am not sure if I am allowed to post here, but here is my 2 cents. You are right to feel the way you do. It is way safer than trusting getting hurt/into danger and then learning a vicious lesson! What you are doing is protecting yourself and following your gut instinct and most of the time gut instincts are always right! My advice is to keep things the way they are, don't be too freaked out, but don't let your guard down either. Don't give out your personal details to him and do not divulge too much stuff, particularly your plans, to him.
Don't worry too much about why he still feels the need to remain anonymous after all this time, but you could ask him in a non-threatening and very light way and see what he says. He, probably, is fighting his own demons who knows?
I hope this helps a little.
Daily I worry for the safety of my young sons - but worry achieves nothing! So I pray for their safety!