Alex, actually I think men often use "I'm fine" and "Fine by me" in the way you point out as the female fashion (or Mr Gray does) only the secondary sense ("I'm hurt, dumbass, leave me alone") is, kind of, less meant to be detected at once.

There is a line I recall J.R. Ewing (in Dallas) would say sometimes when doing business: "I didn't hear that last thing you said. Now let's do some talking..." Spoken right after the other has made a bid or an excuse, that's the active variety of "Fine by me" - the kind you can say when you're in power,. in control and have the room to express "No bullshit with me, now let's talk like I want to talk". "I'm fine" has the same feel of "not enough" but it's said from a position of being powerless.

Great thread, Tessa.