I say live and let live. She has been married before and from what I have read, her family wasn't really sold on the husband. She is an adult, with a lot of experience traveling and competing all over the world. I think she knows what she is doing.
I thought the ex-husband showed some bad form tweeting, even in jest, after the infamous drop at the Masters.
I find it interesting when two athletes date one another. There may be something to the fact that they have a better understanding of the dedication and focus it takes to succeed. Kind of like Andre Agassi's tennis career was a lot more successful after he married Steffi Graf than when he was married to Brooke Shields.
"There is so little love in the world and yet so much."