The chances are very likely this is your fiance's child. As you felt the ovulation on the 2nd and the intercourse with your fiance happened from the 3rd to the 7th, that would have been the most likely time for you to become pregnant. Usually, the window between ovulation and conception is very minimal, 2-3 days long. Since your "window" would have been expired by around the 5th, and you were with your fiance during that period, the chances are high that the child is your fiance's. Also, according to your timeframe on 10/25 of being 9 weeks along, that should calculate to approx. late August/early September. Therefore, it is most likely the 3rd or 4th of September when conception took place. I would have to believe this child is your fiance's. If there is any doubt after birth, however, you could always have a paternity test done, although it seems as though it will be unnecessary.