The Moon of Lust, Betrayal & Revenge

Stella Storm is a professor of mathematics, now assigned to a space mission to the edge of the solar system. While she is there she falls in love with an indigenous female, Ellie. Ellie takes a job with the same space team as Stella but on different projects. Ironically, Stella and Ellie met because of Stella's break up with another indigenous female Michelle. Ellie had stolen Michelle away from Stella, and rather than becoming enemies, they became friends.
When the short-lived romance of Ellie and Michelle ended in ugly fashion, Ellie and Stella became lovers. The two lovers work on opposite sides of the moon and Stella's absence along with the nasty breakup with Michelle has caused Ellie extreme bouts of depression and anxiety. Stella recognizes the symptoms and arranges for Ellie to meet Aki a friend of Stella's from Earth. Aki runs a therapeutic massage business on Charon and using very unconventional methods can treat the root causes of Ellie's depression.
The situation still becomes quite convoluted when Ellie unintentionally falls for Aki, the gorgeous Asian masseuse, and agrees to marry her. But forgets to tell Stella.