Kinda sad when someone cites an off screen romance as good as it got.
But Trek has always handled relationships in a rather juvenile fashion. Either they just act fundamentally silly, go on about how they're having sex without actually saying it directly, or both for the most part.
Kassidy and Sisko were believable.. but also kinda bland as a couple. And how that relationship survived her being a smuggler for terrorists is beyond me. It wasn't even brought up, also odd considering how berserk and nuts Sisko went over the Maquis.