“So where does the secure attachment come from? As more studies become available, there is increasing evidence that a secure attachment style doesn't originate from a single source. The equation of a caring and sensitive parent producing a secure-for-life child is too one-dimensional; instead it seems that an entire mosaic of factors comes together to create this attachment pattern: our early connection with our parents, our genes, and also something else- our romantic experiences as adults. On average, about 70 to 75 percent of adults remain consistently in the same attachment category at different points in their lives, while the remaining 25 to 30 percent of the population report a change in their attachment style.
Researchers attribute this change to romantic relationships in adulthood that are so powerful that they actually revise our most basic beliefs and attitudes toward connectedness. And yes, that change can happen in both directions- secure people can become less secure and people who were originally insecure can become increasingly secure. If you are insecure, this piece of information is vital and could be your ticket to happiness in relationships. If you are secure, you should be aware of this finding because you have a lot to lose by becoming less secure. p140”