You know the type: They go on one magical date with someone, and suddenly they're scheming to backpack through the Swiss Alps with them next summer. But when you ask them about their love interest a month later, they're oh so over it. For some people, romance is almost always a whirlwind — and interestingly, the Myers-Briggs personality types who fall in and out of love quickly happen to have a few traits in common.
While the Thinking/Feeling and Introvert/Extrovert preferences certainly come into play in your dating style and relationships, they don't seem to have much of an impact on whether you're the type to fall fast and move on just as quickly. However, the other two functions do play a significant role in this tendency. A Sensor (as opposed to an Intuitive) may be more likely to end up in a string of short-lived but passionate relationships because they like to live in the here and now, relying on their senses and other immediately available information to drive their decisions. Moreover, a Perceiver may be more prone to this behavior in their relationships, because they are inherently more spontaneous and prefer to act on impulse (as opposed to a Judger, who plans every detail of their life).
There's nothing wrong with whirlwind romances, as long as both people involved are on the same page to prevent hurt feelings. But if you're seeking a steady, slow burn, just be aware that these types can be a tad unpredictable in the love department.