No sorry, I pulled it straight out of my ass.
Or rather, I'm pretty sure I read about a study a long while back, from like finland or japan, on life expectancy. But it also aligned well with my world view so I didn't really question it, and dont have it saved anywhere. I dont know how much of it is still, or was ever true... but I for sure would lose several years to stress and frustration being married over staying single.
The happiness I've read about more recently, but the above applies here as well, though I'm more confident that this is a real thing.