Why Some Guys Bail Without Warning

Have you ever been with a guy who bolted without ever having sent up a red flare? Experts say some men seek out--consciously or subconsciously--shorter term, exclusive relationships for anywhere from two to 12 months, with no intention of going further. One theory as to why: These serial monogamists are chasing that intoxicating feeling of euphoria that's felt most intensely at the beginning of a romance.

"At the start, there's a physical high from the sexual attraction two people have for each other, and it's also exciting because you're experiencing a lot of firsts together," says Los Angeles psychotherapist Vanessa Bell, PhD. Inevitably, though, you reach a plateau, and that's when some men look for an exit. "It's not that they don't like relationships," insists Bell. "It's that they'd rather not deal with long-term ones."

In other words, they get out while the getting is truly still good. Which begs the question: How do you avoid being blindsided by a there-one-day-gone-the-next type? You can often spot this kind of guy early on. He has a wandering eye, tends to be vague about his plans, and has never had a relationship that lasted longer than 12 months.

Down the line, there isn't a precise moment or scenario that causes a switch to flip in a flighty guy's brain, but there are usually precursors--relatively minor things, such as a bout of jealousy or a temporary separation, present a significant relationship hurdle for a guy who isn't committed enough to ride out a rough patch.

During these trying times, Krista Bloom, PhD, author of The Ultimate Compatibility Quiz, suggests asking yourself: Does he avoid talking about serious topics? Is he suddenly not as available? Is he less affectionate than normal? If the answer to any of these questions is yes, beware--he could have one foot out the door.