Why and when did othello say: ", no more. he can come whenever he wants. i won't refuse you anything

In lines 83-84 of  Act III, scene 3, Othello says "Prithee, no more. Let him come when he will,  I will deny thee nothing." He says this to Desdemona, who is urging that he speak with Cassio and reinstate him as lieutenant. Although he says that he will speak to him, he is evasive about when he will do it, and he just wants to be left alone.