2 months is no time .when you have unprotected intercourse
for 8-12 months and don't get pregnant ,then it is a matter ofcncern and needs to be evaluated with the help of tests.every female( in the reproductive age group) menstrautes and ovulates every month but pregnancy
doesn't occur every month as a number of factors play their role in conception.
Second the matter of concern is delayed periods for the lasr two cycles.with the information you gave i can suggest a pelvic ultrasound
to rule out pcod
The answer to your question about the time period the ovum(egg) survives is 24-48 hrs.