Short story identification

I'm trying to remember the title or author of a short story I read (I think in some sf/f genre magazine) back in the 1980s or early 1990s. The main character was a college art prof who did consulting on handwriting analysis. He gets contacted by some shadowy group who want info he can glean from the correspondence of a pair of lovers. She's married, and her lover is working on some super secret science project. The letters talk about their affair, whether her husband (who they only refer to by his initial and who seems oddly resigned to something) knows about them, and vague things about the project but no specifics. Our main character ends up not being able to provide too much to his employers and they go on their way. At the end of the story, he starts a new class of freshmen level art, and recognizes a very immature version of the woman's handwriting. He realizes that the project was time travel, the letters were from the future, and he's the husband (who's initial matches his) in the future. 

This ring a bell for anyone?