Denial interferes with the ability to act rationally.
I had a female friend who told me her boyfriend proposed to her. From a previous discussion with him, I knew that he was going to want to live off her money. I warned her against marrying him. I even reminded her that she overheard the way he was talking about it. Nevertheless, she was in denial and refused to believe the truth.
A month after the wedding she called me, crying, and said they had a fight. I asked what happened. She told me he wanted her to pay all the bills. His reasoning was that they are living in her apartment so she should pay all the bills. Imagine that?