There are a lot more romance options in Mass Effect 3 for the PC, PS3, and Xbox 360 than there were in previous games. They have even added some same sex romance options for both males and females.
Several options are only available if they were continued from the previous game though, so check the list below to see your available options.
Ashley Williams
Diana Allers
Jack (only if continued from Mass Effect 2)
Kaidan Alenko
Liara T’Soni
Miranda Lawson (only if continued from Mass Effect 2)
Steven Cortez
Tali’Zorah vas Normandy (only if continued from Mass Effect 2)
Diana Allers
Garrus Vakarian (only if continued from Mass Effect 2)
Kaidan Alenko
Liara T’Soni
Thane Krios
Samantha Traynor
Female Shepard’s relationship with Jacob Taylor can’t be continued from Mass Effect 2.