There is not much to say on this thread that hasn't been said already.
While not being as keen of male-male sexual activity as the Greeks, it was not unknown nor condemned in Rome. The main thing is that the person of superior rank had to take the active position. If he took the passive position to someone of lower rank, he was condemned as womanly and submissive (I believe it was the alleged passive activity of Caesar in regards to the King of Brithynia, not the homosexual act itself, that was used as fodder by Caesar's opponents).
If there were special rules and regulations in the military about this sort of thing, that is beyond my field of knowledge or my desire to comment.