If Buffy was to believe that her husband, Dr. Evil, was having an affair, she would not confront him. This is a speculative story on what she might do.
Macy’s Phone had a voice calling feature, that could be triggered by random conversations. She was in her car and she heard the phone say, “Calling Dr. Evil.” She tired to get to the phone, and hang it up, but she was too late. The call had gone through.
Later Buffy checks her caller ID on her landline, and finds a hang up call from Agent M’s phone. This can only mean one thing. Dr. Evil is having an affair with Agent M. In spite of the fact, Buffy is herself, having an affair with Javier, this is completely intolerable.
At that moment all sanity leaves Buffy, it her rage. Rather then confront them, she derives a hideous revenge plot. In the cellar of Castle Evil, where the rare foods are stored, is a tank of delicious, delectable, eels. Not the large ocean going Moray Eels which are not good to eat but, the smaller fresh water eels.
She will begin the process of feeding a toxic substance to some of the eels, which will build up in their bodies, rendering them fatal to all who ingest them. Then when Agent M comes to dinner with Fearless Leader, she will feed Agent M and Dr. Evil the poisonous eels, while making she Fearless Leader and herself, only eat the non poisonous ones. As she watches them die in agony, she will gleefully announce that she knows all about their affair, and this is the pay back.
This plans makes her so happy that she laughs and laughs maniacally, and she has completely blocked out the emotional pain, of discovering the “alleged” affair.
This explains the need for Dr. Evil to take extreme precautions about not having Buffy with her history of mental illness, think he is having an affair, even if he is having an affair.