The Ending of Titanic

I watched "Titanic" again a few days back and came to a conclusion that didn't come to me the first time I saw the movie; the ending.

Brock Lovitt spent a small fortune to pick up Rose Dawson. He had to send a helicopter, stow away all her baggage and provide a stateroom and food. He had already spent three years of his life scouring for the diamond, which means he had to get financing for the ship, crew, equipment and submarine. That's a pretty big cash outlay.

The least thing Rose could of done was give him the diamond. Instead, she throws it overboard.

Isn't that just a little selfish?