Owen Harper, portrayed by Burn Gorman, was Torchwood's chief medical officer.
For the most part, he is a pretty shameless womanizer, but like many of the characters on Torchwood, he is not exclusively attracted to the opposite sex.
In the first episode, he is at a bar. He sees a beautiful blonde and is rejected by her. He then sprays her with a magic spray, and you see them walking out to the car together. Then you see her boyfriend running up angry. Owen gives him a glance, sprays the boyfriend, kisses him, and they all climb in the car together. It might not be the greatest example of consent, but it was great to see male bisexuality out in the open in the first episode of a series.
Later in the series, he is undead and unable to enjoy human pleasure like eating, drinking, and sex. He is very depressed and unhappy. In the second season finale, he dies again. As he's dying, he is able to admit that he regrets not being able to pursue a relationship with Toshiko.