Guinea pigs are social animals, so it is best if they live in pairs. Boars should not be placed with sows under any circumstances even for a short period. Please do not breed guinea pigs. It is more difficult than you might think to find good, long term homes for the offspring. It is possible to have guinea pigs neutered but there is some risk involved consult a veterinarian specializing in small animals.
More space is needed for a pair of guinea pigs.
A nest box or house must also be provided. Change the wood shavings regularly to keep the cage clean, dry and healthy. Make your habitat larger if you have room. Place interesting items such as small cardboard or wooden boxes or tubes for your guinea pig to dart into. Keep your guinea pigs in a dry area protected from cold drafts and direct sunlight.