I found myself single again at age 37. At that point in time, any gal who had finished college was in an age range where it was plausible that we could date. Fifteen years is a bit of a stretch, but there are certainly many mainstream couples around where the husband is 15 years older than the wife.
After several years of being single, it was quite a shock to realize that many of the attractive women of marriagable age around me were way too young. No longer was any available SYT fair game.