In the first act of Othello, we are given the impression that Iago and Roderigo are accomplices, and both seek to achieve their own goals through subversion. It quickly becomes obvious that Iago is the truly nefarious one, and Roderigo is more or less along for the ride. This becomes abundantly clear in act 4, scene 2, when Roderigo begins to question why Desdemona never falls for him, despite the great amount of jewels he bequeaths her.
I have wasted myself out of my means. The jewels you have had from me to deliver to Desdemona would half had corrupted a Votaress.Othello, IV.ii.217-19