Ila was the Caprican wife of Adama, and mother to Apollo, Athena, and Zac. She was killed in the Cylon holocaust. (Saga of a Star World) Not much is known about her, except that during their marriage Adama used to irritate her when he bent tableware telekinetically during his evaluation by the Colonial Military Institute. (War of the Gods)
Ila was Adama's only wife.
Notes
Evidently Ila appears younger than Adama (although people can easy refute this claim by stating that Colonials age differently than "Earthlings", and that the picture was taken unspecified yahrens before).