If the news reports are true, Tiger engaged in unprotected sex with multiple women including prostitutes. Assuming he was also engaging in unprotected sex with his wife, he was exposing her to any STD’s these women carried. Such diseases can have have serious implications including death. She apparently trusted him to preserve and protect the sanctity of their marriage which includes protecting his wife and children from harm.
If I was not married and was offered the opportunity to engage in unprotected sex with one of Tiger’s women for half of his wealth, I would not take the risk. I therefore do not see half of his wealth as an unreasonable penalty for exposing her to dangerous diseases and violating her trust that he would live by his wedding vows.
If she in fact contracted a disease as a result of his negligence, then she should be able to recover damages from him. Not the same as awarding her half his fortune.