I doubt that either of them were boy/girl scouts, these are actors we are talking about. It seems that most of them are bipolar or something along those lines. Which sort of makes sense I guess, in order to play a different character convincingly you can't be like regular people. My guess is that Heard was just as volatile as Depp, and probably contributed as much as him to the discord.
One thing to point out is the extremely odd divorce settlement. Who goes to the trouble of doing that, then giving it all away? It seems to me that she probably has a few skeletons in her closet as well, that would be very damaging if it came out. That would be the reason for her bizarre behavior at the deposition (presumably she did not want to be questioned about whatever it was) and the sudden and strange settlement. They probably came to that arrangement to avoid a mutually destructive fight that would damage both of their careers.
Not that it matters to anyone here, their personal and private lives should stay that way: personal and private.