It is not necessary to wait 48 hours between each sexual intercourse when trying to conceive. The fertile window, or the time when a sexual relationship can lead to conception, is relatively short, usually 3 to 4 days. This is because sperm can survive in the woman's body for about that amount of time, while the egg is only viable for around 24 hours after ovulation. Therefore, it is recommended to have intercourse at least every 2 days during this fertile period, ideally every day. The sperm does not need to "mature" inside the woman's body.