In Battlestar Galactica we see plenty of relationship between military themselves (all kind of ranks) and military-civilians in "time of war":
Examples:
Military-military:
- Helo-Athena
- Starbuck-Apollo
- Starbuck-Sam (pilot)
- Apollo-Dualla
Military-Civilian:
- Dualla-Billy
- Starbuck-Sam (before being a pilot)
- Adama-Roslin
...and no one bats an eye.
Nevertheless, one of the big plot points of season 1 is the "secret forbidden relationship" between Boomer and Chief Tyrol. Why is the relationship between Tyrol and Boomer not allowed? Is it because Tyrol is a "Non-commisioned officer"? It's the only difference I can find between him and the rest of the crew.
Relevant quote by Adama, in the argument leading up to Tyrol-Boomer's break up:
Adama: [to Tyrol, after Socinus has been incarcerated] (...) You’ll pay a different price. You’ll have to walk out on that hangar every day knowing that one of your men is in the brig because you couldn’t keep your fly zipped. You are the most experienced non-commissioned officer we have left. You keep my planes flying. I need my planes to fly.