When are women less fertile?
All women are different. The only way for a woman to know when her fertile and less fertile times are is for her to monitor her fertility signals. In general, a woman isn’t fertile after she ovulates each cycle, and for various periods of time before ovulation, but guesses and generalities aren’t very useful, really. The two of you need to research “Natural Family Planning” (there are many books and websites available) and learn how to monitor the fertility signs.