Dear Mr. Ick,
I'm so glad that you're happy to be back in town for the summer. However, I'd like to let you know that it's totally not appropriate for you to sit on the Circulation Desk. Also, although it might make me sound prudish, I'm not comfortable with you asking me if I'm "still married". Just so you know, YES, I AM, and even if I wasn't, I WOULD HAVE LIED. That's how much you skeeve me out. I realize that since you habitually hit on the youngest female member of the staff, the advances are not serious. But they're still unwanted.
Your local librarian