It's poor form to date a friend's former partner.
Serra, who is single, used to flirt with her friend Gloria's handsome boyfriend and just learned that Gloria broke up with him.
Serra wants a handsome boyfriend.
Serra decides against dating Gloria's ex and starts dating another handsome man she just met.
Serra starts dating Gloria's ex boyfriend, and he tells her about Gloria's sexual fantasies.
Gloria feels comfortable knowing that her ex will not share intimate details about her with Serra.
Gloria finds out about it and feels violated.