No need to apologize, Francesco, for starting the thread on Desdemona. It is obviously an important part of the play. My comment was meant more for my sake, in order to keep me from intermingling the synopsis and the analysis too much. There seems to be a curious mix of fatalism and responsibility in the play. Othello trusts Iago more than Desdemona, Emilia remains silent, and Cassio lets down his guard.
All actions allow certain things to result.