Political Calculations purports to offer a calculation for if your marriage will last. I couldn’t get it to work, although that may be because I put in my mother’s information and the calculator refuses to believe someone could get married at 15. But she did. And she’s been married 46 years to the same guy. My MIL got married at 16 and she’s been married to the same guy for 47 years. I got married at 26 and I’ve been married to the same guy for 18 years.
I figure we’ll see 45 as well. Assuming we both live that long.