Welcome to the forum. I hope you plan on either keeping them separated at all times or getting the male pig neutered. here is a major overpopulation of animals (even guinea pigs) and this overpopulation causes over 2 million animals to get euthanized each year. Each animal born takes a home from another animal and causes an innocent creature to get euthanized. I'm certain you don't want to be a contributor to this problem.
Breeding is also very risky to your animals' health and life. Please take some time to read this link Breeding Guinea Pigs