I don't think this is accurate, but perhaps it matters how you slice the data. Women's mental health has been steadily declining across all strata for decades - faster and worse than men's. It's at record lows now, irrespective of whether they are single, married, or with kids. For example, [the UK recorded a 46% increase in mental health issues among women aged 16-64 since 1993.](https://digital.nhs.uk/data-and-information/publications/sta...) Further, when we look at the data between single and married women, [married women in the U.S. General Social Survey (GSS) are about 78% more likely to describe themselves as “very happy”, while never-married women are about twice as likely to say they are “not too happy”.](https://statmodeling.stat.columbia.edu/2024/08/27/marriage-h...)

The irony with all this data is that as women have achieved parity with men in all kinds of domains, their happiness has commensurately declined. This is one of those hot button topics which most sociologists refuse to research.