From Longman Dictionary of Contemporary Englishfor my sinsfor my sinsBritish English spokenXX an expression used to suggest jokingly that you have to do something as a punishment I work at head office now, for my sins. → sin
Examples from the Corpus
for my sins• I am Araminta Merchiston, Lady Merchiston's daughter - for my sins!• And because of this he has paid the price for my sins and your sins. 