Rosiegirl has it right - these 'Aunts' married my Dad's brothers and step-brothers, and most of them are second or third wives (Dad is the only brother among them who has not divorced and remarried).
In fact, one Aunt is only 6 years older than one of her stepsons. So there's some... confusion... at various events. Especially when my Husband is older than women I am (under sufferance, at the request of my Uncles) referring to as 'Aunt So-and-So'.
To make things more confusing again! Uncle A married Aunt A when he was in his 20s and had 3 kids - Kid #1,#2 & #3.
Divorced. Married Aunt B. Had 2 more kids (#4 & #5). Divorced again.
Before he married Aunt C, Kid #1 had his own children (Grandkids #1 & #2).
Uncle married Aunt C, and has since had Kids #6 & #7, who are the Aunt and Uncle of Grandkids #1 & #2, even though Grandkids #1 & #2 are older than 'Aunt and Uncle - Kids #6!