From Battlestar Wiki, the free, open content Battlestar Galactica encyclopedia and episode guide
Shevon is a prostitute residing on Cloud Nine with her daughter, Paya. Through means unknown, Lee Adama began to solicit her services sometime after his ordeal during the operation to destroy the Resurrection Ship. Adama likely sought her out because Shevon reminded him of a love he left behind on the Twelve Colonies.
More than a sexual relationship, Shevon also comforted Adama. Though unbeknownst to the captain, she was working for the black market's leader, Phelan. Upon Shevon summoning Adama to Cloud Nine, Adama was attacked and left unconscious. After regaining consciousness, he had discovered that Phelan left him Commander Jack Fisk's killer, complete with the murder weapon.
Despite the gesture, Tom Zarek relenquished information that Phelan was aboard the freighter Prometheus with Shevon and Paya. Summarily, she was released upon Phelan's death at Adama's hand, though Shevon made it clear to Adama that she was in no way similar to the woman he had left behind on the Colonies (Black Market).