She's only going to live nine years, she doesn't need that lung.
I assume the Ocampans must mate for life, since they don't live long enough to get sick of each other.. and she was probably at a loss as to how to break up with someone and what was required. I bet she took all her cues from the soap operas she watched in Future's End!
Kes outright states this in the episode. They mate for life, no jealously, infidelity nothing. The concept is beyond her. Which leads the Doctor to point out, "Your homeworld must have very dry literature."
teacake, that's a great spin on Neelix, now if only the show actually used that instead of what we got.