In-game relationships are a double-edged sword. Some people use it as an effective roleplay device to further a story - other people use online games as their own personal 1-900-NASTY-TEXT service. For people who have existing real-life relationships, this can even become quite destructive.
Keeping in-character things in character (and at least in my mind avoiding the emote-orgies that become way too common in MUDs), I believe the \"standard\" culture of planeshift has evolved to expect a marriage to be an exclusive matter. The Diaboli will most likely shun marriage, after all, it\'s almost religious! For those of you wishing a harem, officiated marriages are probably not the way to go.