An interesting hate/love romantic couple is the couple who compete.
Early CSI includes an episode where a husband deliberately alters his wife's mountaineering map, so he can beat her time. And Law & Order: Criminal Intent presents a Hitchcock-like episode where a lawyer husband frames his lawyer wife for supposedly trying to kill him--mostly because she made him look bad at the office.
Romances, of course, need happier endings. So how does the competitive couple resolve their sense of competition? I mention B'Elanna and Tom Paris in an earlier post--they resolve their competitiveness by not competing over the same stuff.
In the Lords of the Underworld novels, Strider--who carries within him the demon of Defeat (he feels challenged by everybody and everything)--resolves his feelings of competition by aligning himself with his lover, Kaia: her desire to excel becomes something he wants her to exercise as much as she does (I consider this book and its resolution one of the best of the series).
Many M/M sports novels revolve around the problem of competition. I especially appreciate how the writers--who obviously know their milieu--so rarely resolve the issue by having the male leads sacrifice opportunities and positions for each other. Because, okay, this is sports, and players just don't do that. Wanting to be the best and achieve the best, to make it to the World Series or Stanley Cup Championship or Superbowl or Olympics is the point. Take that away and come on, it's lazy kids sitting on a couch (says this writer who loves to sit lazily on her couch).
The intense level of competition makes the romance harder to solve. The best authors take the same approach as Goalie Interference by Avon Gale and Piper Vaughn--the players recognize that their competitiveness makes them better: their games have improved.
The goal--ha ha--is construction rather than destruction: the couple who can build on their competitiveness and create a unique relationship are the mature couple with a potential future.