https://www.sciencedaily.com/releases/2022/03/220331151551.htm

The research team from UCL and the University of St Andrews found that the 70s cohort had a 50/50 chance of splitting or staying (or marrying) their first partner. The youngest cohort was significantly more likely to separate from their partners than to marry them.

When looking at how long people stayed together, within the two oldest cohorts, 25%-27% of couples had separated within two years from the start of cohabitation. This figure is 43% in the youngest cohort suggesting that first cohabiting partnerships have become less stable and do not last as long among younger generations.