I used to breed guinea pigs myself, have had many successful litters, males will care as much as the females and as for the immediate mating it takes about 7-10 days for the mother o be fertile again so dont worry too much let him stay for a couple of days to enjoy his baby then remove him. the best thing to do then is get him neutered, it costs about �20 then he can stay with his family and no need for a new hutch. bear in mind that you may have problems if the baby is a boy though. if so he will also need neutering, or perhaps rehoming away when older or as he matures he will compete with his father for dominance which will result in fighting. if it is a girl no problems!
sexing the guinea pigs =
hold the guinea pig obviously belly up, and press down just above the genital area with your thumb if its a boy a penis will pop out. if nothing pops out then she is a girl. be sure to apply enough pressure though dont be too gentle.
you will not be able to determine the sex untill about 6 weeks of age though. they all look the same until then.
If you do decide to remove one of the parents then remove the dad please dont remove the mum unless you are prepared to express her milk (which is very difficult) as the baby needs this for atleast the first 6 weeks of life to provide all the required nutrients and anti bodies as do human babies!
guinea pigs need company so the most ideal thing would be to neuter the males. you are lucky she only had one. i never had a littler smaller than 3.
Unfortunately if you buy guinea pigs from pet shops it is common you will end up with pregnant ones as they are bread in captivity for that purpose lots of piggies to sell to shops. best place to look for guinea pigs are rescue centres and breeders.
Oh and go ahead handle the little cutie as much as you want the mother will never neglect her young because of human touch unlike many other animals.