Much of what Emilia is talking about focusing the blame for men either cheating on their husbands or simply failing to keep up the relationship solely on the men. Her response is to Desdemona's question as to whether she would sleep around to gain the whole world.
But I do think it is their husbands' faults
If wives do fall; say that they slack their duties
And pour our treasures into foreign laps,
Or else break out in peevish jealousies,
Throwing restraint upon us, or say they strike us,(95)
Or scant our former having in despite,
Why, we have galls, and though we have some grace,
Yet have we some revenge.
She says that it is a man's fault if the woman has to turn elsewhere for love, it is their neglect that makes them do so, particularly if the husband is restrictive or abusive.
She ends with the phrase "The ills we do, their wills instruct us so," suggesting that anything they might do wrong, they've learned from their husband's misdeeds.