to your dying day
From Longman Dictionary of Contemporary Englishto your dying dayto your dying dayfor the rest of your life He regretted the decision to his dying day. → dyingExamples from the Corpusto your dying day• He chose Everton over Arsenal and will regret that decision to his dying day.• Nixon believed to his dying day, and with good reason, that Kennedy had stolen the contest, especially in Illinois.• He would insist to his dying day that an arctic wolf had savaged him.