Although the real question is, why didn't the mathematician correct me?
Just realized today that…
Just realized today that I'd been thinking that Kevin and I have been together for 24 years this May, and we should do something to celebrate our 25th anniversary next year in a biggish way, except that I'm pretty sure my math is totally wrong. If we met in May (or possibly April?) 1992, then it'll be 23 years this May, right? Jeez, how many years have I been getting that wrong? Math is hard.