A bunny or two.

[robkelk]

Remember, these are attractive, intelligent, well-educated girls -- and high-spirited, too; they know their own worth, so neither is likely to submissively say, "Anything for his happiness."

That isn't necessarily how they'd feel about bigamy, though (as many of Heinlein's novels point out). "We've found the ideal life-partner, there's no way either of us will settle for second-best, and he's not property any more than we are - let's share."

Mind you, the aliens might be monogamous for life by instinct... which makes this discusion moot. If it's in your DNA-equivalent, you're stuck with it.
--
Rob Kelk
"Governments have no right to question the loyalty of those who oppose
them. Adversaries remain citizens of the same state, common subjects of
the same sovereign, servants of the same law."

- Michael Ignatieff, addressing Stanford University in 2012