: I thought Iago's wife stole it, in return for Iago's... "favours," shall we say?
Desdemona drops the handkerchief when Othello pushes it away from him (Act 3, scene3, line 284). Emilia (Iago's wife) picks it up and intends to get it duplicated then return it to Desdemona. When she gives it to Iago, she believed he would give it back to Desdemaon when he had had it copied.