There’s no point even trying to compare sex in the context of Petraeus’ affairs and DADT. It’s apples and oranges.  DADT was never an issue of national security, although often argued by proponents. This was made clear upon its repeal and even before when you compared the policies of Australia, Canada, etc. When anyone with a high security clearance puts themselves in a position of vulnerability as Petraeus did it’s a BIG deal. It opens up all kinds of threats beyond leaking classified information - like blackmail from foreign and domestic enemies aware of these ethical ‘transgressions’.