1) The myth of "pre-cum" containing actual sperm only applies if you have sex back to back. He still has sperm inside him that comes out with pre-cum if he does not urinate before having sex again. This is often a cause for pregnancy; even if he pulls out before he ejaculates, if he has not urinated since the last time he came, the pre-cum will impregnate.

2) Sperm can live inside a woman's body for up to a week. To be safe, do not have unprotected sex within 10 days of your next ovulation. These are the "green days" in your <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">Eve</a> calendar. 

3) While resources like the <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">Eve</a> app are incredibly helpful, make sure you have logged three precise periods before relying on the app to have unprotected sex. It is very important that your ovulation dates are as precise as possible. This is the information you used to ensure that you are having unprotected sex at the safe times.