Mary's husband has been cheating on her with another woman for the past several months. while many of her friends realize that this is happening, mary is able to explain away all evidence of his infidelity. according to sigmund freud, which defense mechanism is she using

According to Sigmund Freud, she is using denial.

Mary still cannot cope with the fact that her husband is cheating on her with another woman, despite the evidence she has been presented with. Her friends are trying to prove to her that her husband is being unfaithful to her, but she doesn't accept that evidence and is able to deny it by finding excuses for him.