I don't know her but my feeling is no. It feels very strange to downgrade her life this much to live in poverty instead.

IF she were using you, she would have stayed with you and enjoyed her wealthy lifestyle - whether she is even cheating or not. She could still 'pretend' (again, IF that is even what she is doing) to love you and enjoy a life of luxury.

To me, it seems more of a mental health issue/crisis & that she needs help rather than judgment.

How about couple's counselling, is she open to that?