I'm always disappointed when I see a bunch of unmarried dwarves. The forums often have little schemes to fix that, but it would be interesting to install some more direct approaches. Also, I know a lot of romance is going on that I just can't observe without pausing the game and checking everyone's status screen.
(I often mod the game to play as other races, so if some of these suggestions seem weird for beard on beard action, it's because I'm not approaching the situation from that context.)
Single's BarSupposedly the Tavern update is coming up next, so I'm not going to attempt to be specific until I see it, but the basic gist would be that single dwarves could go to a designated area where they seek other single dwarves. Interactions in the single's bar would be more likely to create romantic thoughts. The "single's bar" need not be taken literally, just a designated area, like at a beach or a park or something.
A relevant amusing sign:
http://9gag.com/gag/aNebRmr/sex-is-allowed-in-the-park-i-like-living-in-copenhagen-denmark Not that I expect explicit behavior to go on in DF.
AphrodisiacsCertain substances would cause dwarves to enter a more romantic state of mind. Natural aphrodisiacs could be nothing more than a source of amusing accidents, but savvy players could strategically cultivate and distribute crops of them.
Some lists of aphrodisiacs:
http://www.rd.com/slideshows/aphrodisiac-foods http://www.foxnews.com/leisure/2012/02/07/top-10-aphrodisiacs-foods-to-put-in-mood/ http://altmedicine.about.com/od/herbsupplementguide/a/aph.htmDatingI'm sure a lot of romantic interaction goes on, but it's hard for the player to witness it. Visual cues would be more fun. For starts, dwarves could spend their breaks going on dates with other dwarves. So instead of seeing Urist ... On Break, you'll see Urist ... On Date with Shumlik Gastnabreth, with the two dwarves spending their time in the same places. Besides being fun to watch, that should strengthen the relationship between the lovers, since they are spending time with their lover specifically and not waiting for random chance to put them in the same area at the same time. The date should also improve their mood, assuming it goes well and perhaps assuming it's not programmed to not go well.
It could also be interesting to display a dating blow-by-blow on the reports screen. "Urist tries to kiss Shumlik, but the kiss is deflect by her (sheep wool hood)." "Urist: I saw a fantastic statue with my date. I'm so happy." "Urist reaches for Shumlik's hand. Shumlik accepts Urist's hand. Shumlik: Teehee." That's probably something players will want the option to turn on and off.
Arranged MarriageWhen all else fails, there should be a way to say "alright you two, you're married now." Arranged marriage was definitely the norm in the pre-1400s world. I suspect many players would use this to breed a subrace of super dwarves.
There are also little things that could be done, like showing an "Attend Wedding" message instead of "Attend Party" message when dwarves get married. Or some kind of heart symbol could appear when dwarves are experiencing romantic thoughts. It would be interesting to see a Beauty stat show up on the stats page that could impact their love life.
For all I know these happen already, but dwarves could feel romance towards another dwarf who saves them during combat, or jealousy over lovers could provide dwarves with motivation to commit crime and cause trouble.
There's probably a lot of potential for romance in Adventure mode too, but I don't really play it, so I leave that to you.