Tina
How does a seemingly intelligent woman like Tina fall in love with a control freak A Hole like Gabe? He gave her many clues to his character flaws long before he murdered her. I say murder becaues he did purposely allow her to drown in the waters off Australia.
He only married her after she started to see someone new, a nice guy that she rejected. She would still be alive had she stayed with him instead of believing Gabe's BS...