Kari Matchett play's Beth, who is Thomas, the cute EPS guy's ex-wife. Beth first appears in Episode 1, "Wax Lion," when Thomas is injured and she is called because she's still his emergency contact. She returns when Sharon pursues a relationship with her on and off throughout the rest of the season.
Episode 1, "Wax Lion"
Episode 2, "Pink Flamingos"
Episode 9, "Safety Canary"
It was revealed in commentary on Episode 9, "Safety Canary," that the show's creators, Todd Holland and Bryan Fuller, had intended on the plot line involving Sharon and Beth to continue on into the second season, had the show been picked up. In their storyline, because Beth had slept with Thomas directly before sleeping with Sharon in Ep. 9, this would have resulted in an unplanned pregnancy for Sharon, which Beth would have then needed to explain to everyone.