Have You Ever Wondered?

What goes on in peoples heads when you give them an ultimatum? if you say to someone..  " if this has happened its me or her.." and you get a blank response? and deep down in youre heart you now that something has happened, but they cherish youre friendship too much to tell you? im the kind of person that finds out everything that goes on, even if it kills me, but when you can blatently see it happening on youre head, and you know for certain its happened.. what do you do about it? what would you do?