Werebeast disasters have ended more than one of my forts. My custom werewolf for spellcrafts somehow ends up spreading the curse even to people that didn't get bit according to combat logs. And I have no idea how. I've just about gone to the vampire method of only spreading if you drink their blood. But that's not nearly as fun.
My experiments with love making appear to have born fruit. Weird fruit, sure, but fruit nonetheless.
So, lovers barb is a plant in Spellcrafts that increases personality facets like gregariousness, tolerance, love propensity and lust propensity, and reduces hate propensity. It turns out, this does indeed increase the chances of forming relationships, with, in my last test, the starting seven of two of the three females and all four males ending up in relationships. Both women were in romantic relationships with one another, and each of them was in romantic relationships with each of the four men. Each of them married one of the men, I'm not sure if the other guys are getting cut out or how the game handles that. A couple of the men had relationships with one another too. The seventh dwarf, the remaining woman, was kindred spirits and friends with every other dwarf, but formed no romantic relationships. Asexual/aromantic presumably.
Of all the migrants that moved in, they all very quickly formed friendships but most of them were already married, and after about six months or so none had formed new romantic relationships. So it looks as though dwarves once married will not pursue other potential romances, but before marriage can form at least up to four concurrent romantic relationships. Lovers acquired before marriage are still listed as lovers, not sure if they'll continue to socialize and treat one another as lovers, though.
The lovers barb plant and alcohol syndromes are definitely turning up the heat though. Typically of the starting seven you'd see maybe two or three relationships, not a six dwarf series of love quadrangles.
Obviously the question is, can we go deeper?