Was it wrong of her to pursue her happiness and lust, rather than being stuck in an unhappy marriage?
Despite the age difference, the two semed to be genuinely in love. In many cultures, and in the past, this would have been legal.
In Japan, first cousins can legally marry. In the west, it is illegal. Polygamy is also illegal, but in many cultures it is.
The age thing is also very arbitrary. Let;s say you have sex with a 15 year old one minute before her birthday. You are a pedophile and rapist and thrown in jail. However, if you have sex with her one minute later, she has reached the age of consent and it is perfectly legal.
This is clearly not an objective black and white issues, and where the line is drawn is depenendent and different in many cultures.
We can judge her, but in the end both the sps we see and all of us seeing them are no better than her in the laws eyes. We are all breaking some law that prevents us from satisfying our lust, even though all parties are consenting.