Healthy competition?

I've always admired the couples brave enough to run road races together. Not only for their endurance, but for their ability to not let an athletic rivalry ruin their relationship.

There's a moment in every relationship when you see your once demure partner's competitive side.

It can start with something as innocuous as a road trip game of Cow Poker. Then, before you know it, your significant other is rubbing her three-digit point tally in your face and ending every sentence with "boo yeah."

No joke, I know a couple who broke up over a nasty game of cards.

Some couples thrive by sharing competitive spirits. It can add fuel to a relationship and sometimes result in some really good conciliatory makeout sessions.

But in other cases, when a relationship's competitive equilibrium is off, a simple board game rivalry can quickly put you in the danger zone.

Have you ever been put off by someone's competitive side?