Roderigo feels his friend Iago, who is helping him win the love of Desdemona, should know about what is happening in Desdemona’s life. Iago defends himself by explaining Desdemona’s marriage to Othello was sudden, and he had no knowledge of it. In order to protect his interests, Iago convinces Roderigo to inform Desdemona’s father of his daughter’s new marriage to cause a lot of problems throughout the rest of the play, “Never tell me; I take it much kindly, that thou, Iago, who hast had my purse, as if the strings were thine, shouldn’t know of this” [Translation: Psh! Don't say that. Iago, I am not pleased that you've known about this, especially since I've given you access to my wallet as if it were your own. ]. ACT 1 SCENE 3 PAGE 3
Just like Othello, Roderigo himself was so consumed by jealousy that he immediately gives into Iago and follows whatever Iago says without much consideration.