She was an Ocampan slave girl to her Kazon masters.
I can imagine while doing Business with the kazon, it made sense for Neelix at one point to stay over.
A bear skin teepee?
The point is that they tell Kes to go and keep Neelix warm or they'll cut her fingers off.
She gets in there, tries to do a sexy dance but just starts bawling.
Neelix apologises, offers her the bed, and he sets up his kit on the floor.
They talk all night.
I can see this situation playing out a few times before he finally "steals" the slavegirl from her legally entitled masters with Janeways help.
Before Voyager he wouldn't know much about her, and her species has been hiding underground for the last 10 centuries.
The sex talk might have happened early after he saved her.
The kitchenrat was told that they would have sex in two years.
Neelix marked it on his calendar.