This article is from the NYPD Blue FAQ, by Dave Chapman, Alan Sepinwall and Jeff Knapp with numerous contributions by others.
Bobby and Diane are engaged, though it is a secret from
everyone. Bobby had initially proposed during "Moby Greg
(4.01)" but Diane didn't finally accept until "A Wrenching
The Job does not like intra-precinct romances, as explained
with the introduction of Adrienne Lesniak, who was transferred
in to the 1-5 due to a relationship with one of the detecives
in her precinct (of course, we know how that ended).
Fancy seems to be turning a blind eye to the situation, which
could potentially make for some interesting plot conflicts
when Kim Delaney's contract expires (which appears will never
It makes one wonder how they will handle the wedding...