Caroline Benn died before Tony
I think everyone knows that 
Besides, if his family's wealth came from his wife's side, perhaps he felt it would be unfair of him to cause them to lose out because of inheritance tax, and left it to his wife.
I don't think the above means 'he left his money to his wife', I took it to mean that Tony left the management of her own money to his wife Caroline whilst she was alive and left her to decide what to do re any inheritance etc. Presumably he may have inherited from her, I don't know. That's their business as long as everything was done legally.
Perfectly plain to me (although it could be misread by those who wish to misconstrue it I suppose).
Is a new relationship possible without sex?
beyond most of us, even professionals, especially after paying tax.