lifeandsoul
First of all, this may be shutting the stable door after the horse has bolted, but the next time your wife asks if some woman is good looking, affect a bored look and reply "Spose so...some men might like that, but I think she looks a bit ovbious".
You may want to write that down on a card and keep it with you for ready reference.
One point - you say your wife is constantly accusing you of having an affair with this woman.
How did she get to this place? Has she met her? Have you ever been out with your wife in a group where this woman was? Do you keep referring to her?
I ask because something must've sewn that seed.
I would also suggest that you absolutely steer clear of coming onto this woman.
If she reciprocates, you stand a very good chance of losing your family.
If she doesn't reciprocate, you stand a very good chance of being hauled over the coals for 'inappropriate workplace behaviour'.
In future only have gay male secretaries. Zero chance of you having an affair with him, and he will protect you from making bad clothing decisions.
Voila.