I must have bad luck as it has happened 6 times now.
oil to blame once (wg's choice of lube), 4 times they were to small and split, and one split in covered oral. That time the girl insisted she did covered oral (although offered owo over phone!) but got so vigorous the end split and then when I came she swallowed the lot!.
When one split in sex, I sensed something was not correct and stopped, the wg got awkward and wanted to know how long had it been like that and why did I not stop earlier!
On another occasion it split and we had to spend some time removing bits of condom from her, when that was done I put another on and was told "you only have few minutes left, be quick" !