Imagine a still newly Justice League, each hero has been around alredy for some years before the JL formed.
None of them still revealed their identity to everyone, obiously there are some that reavelead between their friends.
Like Green Lantern (Hal Jordan) and Flash (Barry Allen), or the Tryinity.
Batman and Superman are pretty close, and even if they don't openly admit it they are married, that's what the JL thinks.
Superman always looks at Batman with loving eyes, And Superman is the only one allowed to stand so close to the Bat.
Batman dosen't accept food or coffee from anyone except Superman during Watchtower duties too.
They are obviously married, even if they don't openly admit it.
Then the day finally came, everyone finally revealed their identity to the League, and after the shock of finding out that Bruce Wayne is the Batman a question finally popped.
Oliver Queen (Green Arrow): Anyway, when did you two get married? and WHY wasn't I invited?
Bruce (Batman): Married? who?
Barry (Flash): You and Big Blue, I mean Clark
Clark (Superman): We're not married.... well, I am married, but not to Bruce. My wife is Lois Lane, she's a colleague of mine at the planet
Hal Jordan (Green Lantern): But you two-
Barry put a hand on his friend mouth stopping him from speaking
Bruce: why did you ask?
Oliver understanding the situation: Well, Clark was the olny one that you acted friendly and close with, so at the time it was a logical conclusion
Clark all smiley: well, that's because we're best friends!
Diana looked at the other 3: I know, I'll explain to you 3 later....
and that's how the Justice League found out that Superman and Batman were not married, and Diana always knew
