Divorce in later life is becoming more common – and scientists are beginning to explore the surprisingly deep impact this can have on adult children and their relationships.

Divorce is greying.

The US has one of the highest divorce rates in the world, even though over the past four decades, it has fallen among younger couples. Instead, middle-aged and older adults have taken over. In fact, adults aged 65 and older are now the only age group in the US with a growing divorce rate. For the over-50s, the rate also rose for decades, but has now stabilised.

Today, roughly 36% of people getting divorced are 50 and older, compared to only 8.7% in 1990. This is known as a "grey divorce".

This tilt towards later-in-life divorce is happening for a mix of reasons, studies suggest. Lives are longer than they used to be, for a start, and older couples may be less willing to put up with unfulfilling marriages than before. Meanwhile, young people are getting married later and have become more selective when choosing a partner. As one researcher puts it, "the United States is progressing toward a system in which marriage is rarer and more stable than it was in the past".

The rise in grey divorce isn't exclusive to the US – it's also happening in ageing populations around the world. One Korean expression says that a marriage should last "until black hair becomes the roots of green onions" – meaning that it is a lifelong commitment. But since the 2000s, more older adults in Korea have been going through hwang-hon divorce, or twilight divorces, to end unfulfilling marriages. Given an average life expectancy of over 80 years for Korean men and women, "those in their 50s and 60s can anticipate another 30 or 40 years of life, and grey divorce can offer a chance at a new chapter in life," the study says. Japan has also seen a rise in "mature" divorces since 1990, and today, grey divorces account for 22% of all divorces there.

Amid this trend, one aspect of grey divorce is beginning to receive more attention: the surprisingly deep and wide-ranging impact the split can have on adult children – and on their relationships with their parents, especially, their fathers.

While researchers have widely studied how young children are affected by divorce, the impact on adult children was long neglected, perhaps because they were assumed to be more mature and better able to cope. However, already in the late 1980s, emerging research found that just like young children, adults reacted to parental divorce with anger, shock and "lingering sadness".

"Many times I've heard adult children say, 'it felt like the rock that was my family […] my support network system that I grew up with […] was sucked into an earthquake fault'", says Carol Hughes, a marriage and family therapist based in southern California and the co-author of Home Will Never Be the Same Again: A Guide for Adult Children of Grey Divorce. "All of a sudden, their parents are divorcing, and they feel like the bottom has fallen out of their........

© BBC