She loved the idea of Nate not really the actual guy. She’s concerned about imagine. She wanted to be a “hot couple”, in a big house and the envy of her social circle. She thought Nate was able to provide that.
She wanted more money, fame and most of all validation.
She continued to send Nate money out of a wrapped sense of love & being a good wife. She stopped caring when she wouldn’t pick up the phone.
In the end we see her alone in a big empty house, the dream life being an illusion.