Sara L. answered 01/25/22
Ivy League Educated - English Major, Minor in Ancient Studies
Hi Jay! This is an interesting question! First, it's important to remember that "Ancient Greece" was not a cultural monolith. The sexual norms in Sparta were very different from Athens, which was in turn different from Thebes, Corinth, Rhodes, Argos, or any of the dozens of powerful city-states throughout the Ancient Greek period. So, no definitive claim can be made about how the "dominant military culture of Ancient Greece" affected anything, because while Sparta certainly had a dominant military culture, Athens on the other hand had barely any land army to speak of. Sparta arguably treated women far better than Athens, due to their intense military culture, which required that the women be trained in combat in order to defend the homestead while the men were off fighting. (Also in order to keep the slaves from revolting, since Spartan society had far more enslaved people than free people.)
However, it can be said that "sexual morals" generally included the idea that a woman should only have sex with her husband (or if she is a slave or concubine, only with the man who has enslaved her), while a man would generally be expected to have sex and romance with other men as well as his wife. This seems to have been true regardless of the strength of a given city-state's military.
To look at the question from another angle, The Sacred Band of Thebes gives an excellent example of a dominant military force that is itself strongly influenced by sexual norms. The Sacred Band of Thebes was an elite army, composed of 300 men partnered off into romantic pairings with each other. It was believed that this would lead the men to fight more ferociously in order to impress their lover, and prevent anyone from fleeing, lest they leave their beloved behind. The Sacred Band was the most powerful army of its time, undefeated for forty years (378-338 BCE), and highly respected. In such a case, there might be some truth to the claim that a dominant military influenced sexual morals, in that most of these men were not expected to have any serious commitments outside of the Band, whereas in most situations men were expected to marry and raise children regardless of their feelings towards other men. However, this is one particular situation, and I believe it doesn't hold a statement about Ancient Greek society as a whole.
Please let me know if you have any additional questions.