I can point you to my own work,
A Mirror Cracked, for an exploration of Andorian culture - which I invented to contrast with the Vulcan tendency toward monogamy.
It's a TnT story. I don't want to spoil all the particulars of the plot, but I had Talas and then Shran appear as characters - both of whom express sexual interest in Tucker. Shran also expresses sexual interest in T'Pol - by sending his wife to seduce Tucker, since quid pro quo would be expected. I set it up in the story that in a quad marriage, the four are faithful to each other - but before the quad is closed (such as Shran being married to only one woman) - it is expected they would seek outside partners. Monogamy is silly to them. I also set up the idea of a human character entering into one of these quad marriages, which will be developed if I write a sequel.
Basically, it was tons of fun imagining a pansexual culture that had no hang ups about sleeping with whomever struck their fancy, without being worried about fidelity. It was also fun to think about the complexity of finding four people who would be sexually and emotionally compatible with each other.
The Andorian stuff was all "B plot" but it was gloriously fun to imagine, especially in contrast with the possessive, monogamy preferred by MU T'Pol.
BTW, I love the idea of a T/Tu/R vee situation! There's loads of possibilities.