My las menstrual cycle was June 18. I have a 28 day cycle. I had a one night stand on the 24. Then I had intercourse wit my boyfriend on the 29. I became fertile on the 28. And if my calculations are correct I started ovulating on July 2. My next cycle was due on July 16 and it hasn't came on yet. I am pregnant like five weeks. How is it possible to b 5 weeks if I was ovulating on the second? Which one is more likely to be the father and how long does sperm live inside the uterus?