Anxiety about being alone, or even being single, can be a powerful driver. It can be powerful enough to distort reality. Illusions become the new normal. A peculiar kind of blindness twists all the horrors of a relationship into something bearable. The intolerable becomes the tolerable. What could not be accepted is now justified, even defended. All of the pain is perceived as being preferable to being alone.
Anxiety can also turn off selectivity. Criteria, expectations and wants are significantly altered. The bar is not set high, but low. Anyone who shows interest is now acceptable. There is no discernment. As long as someone shows a hint of a romantic interest, that person is suitable as a boyfriend or girlfriend, even potential spouse.
The Fast Track to Love
The problems with moving so rapidly is that strangers wind up together with nothing in common. People that know virtually nothing about each other share intimacy on a physical level, but no other. Emotions and urges are at a fevered pitch. For a while, this can work. Passion can sustain a relationship. However, it is not the glue that holds people together for prolonged periods.
Passion Vs. Reality
The romantic, but problematic, idea of love at first sight is built on instant gratification. It does not take into consideration that attachment without knowledge of another can equal difficulty, pain and loss. Love in isolation has never been an effective problem solver. Strong emotions are weak tools in evaluating a decent long-term companion. Minus reason, insight and logic, things can fall apart, quickly.