Also, if I were in your situation, the fact that the seller is my manager's husband could possibly add a few dollars to what I was willing to pay.
Many will assume that if they paid $400+ for a bike and only rode it once or twice, that they should get $350 for it. I have seen bikes on Craigslist several years old where the user is asking retail value new because of the extras (usually a $29 computer, a $3 bottle cage, and a different saddle)... They ignore the issue of new technology on newer bikes, and no warranty. So, if this seller is in that boat, you may need to explain the fact that most bicycles don't hold their value very well.