Here's a Question: Why Not Trust the Wife?

I wonder sometimes why Othello even bothers with Iago. Of course Iago is manipulative and sleeving etc, and Othello did "overhear" Cassio talking about an affair, but wouldn't he believe his own wife over some young advisor? He doesn't even believe Iago's wife, Emilia (who has doubts about Iago's intentions too). Othello had a happy marriage before Iago, so I don't get why he immediately dismisses everything his own, close, lover has to say to him about her loyalty. Even the woman closest to his wife and Iago, what should be the missing link in this mystery, is bitterly dismissed as a liar. Why? These people don't seem any less trustworthy than anyone else in the play, maybe even more so in some situations.

Perhaps this is an example on the lives of women in Shakespeare's day. In terms of testimony, modernly, men and women are about equal. We both have the power to lie and tell the truth at an equal rate and frequency, etc. But maybe then, the women's opinion was not valued as much as a man's. I would not know for sure because I have not studied extensively over the time period. But that is my theory. Societal issues always seem to get in the way. Just think about Othello's appearance, much different than the rest of the cast, and therefore a problem. This is an issue with society, built on past down prejudices and standards. The wife's role can be just another standard, supporting of her husband, but untrustworthy in terms of faithfulness. It's such a shame.