When desdemona asks iago's help, what does he say to her about othello's jealousy? Act 4

He says that it must be some business about the war or
something else that is really bothering him:

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I pray you, be content; 'tis but his
humour:

The business of the state does him
offence,

And he does chide with
you.

There is no
way that Othello, who loved Desdemona so dearly, could really have any problem with
Desdemona.  Of course Iago must also be sure that she doesn't get a real hint as to what
is happening because she might explain it and then Othello might see the
truth!