Axton

Axton is a playable character in the Borderlands franchise. He spent 10 years in the Dahl military force but wasn't great at following the rules. 

Sarah, his wife and commanding officer, divorces and discharges him, letting him know that his latest exploit will lead to death by firing squad. She unofficially suggests that he go AWOL and try his luck on the border planets. 

Axton becomes a mercenary and vault hunter. He continues to wear his ex-wife's dog tags and wedding ring around his neck. 

Axton's bisexuality started in part due to a programming glitch. There was some gender-specific dialogue that didn't quite happen, and so there was a chance to hit on a male (or female) character when you revived him. The writers went with it and added more dialogue in Tiny Tina's Assault on Dragon Keep making his bisexuality more explicit.

Axton, along with Moxxi, Tiny Tina, Mr. Torgue, and Zane Flynt make up the bi cast of the Borderlands franchise.