I've had intact males in the past, and am around a lot of intact males with the dog club, various sports and my local dog group. With my males in the past I haven't had a problem with them peeing inside. But, where I do have a problem is their interaction with other dogs.
Because I and my dogs spend a lot of time around other dogs, I have found that intact males do not interact well once they reach adolescence. Intact males are much more likely to pee on other people and dogs. There's probably 2 in the group of dogs in the local group (out of maybe 50) that are desexed and have on occasion peed on people, but without fail the intact males have all peed on people and other dogs. Invariably the intact dogs stop coming to the group because of this. They also become bossy and obnoxious as adolescents, so no other dogs want to be around them. At competitions, if any dogs get into a fight it's usually the intact ones. At the club, the intact males can do okay in a small group, but they don't do well when the group gets beyond a few dogs. We don't allow intact males in the clubhouse uncrated because invariably they pee, and with the smell they create it's darn hard to stop other dogs doing it.
So there are problems with keeping a dog intact. You will have to work out whether keeping the dog intact will impact on your lifestyle and what you plan on doing with your dog. That's the first priority. But you have time to work that out - what until he's hit adolescence and if it becomes too much don't put it off because of the breeder's whim.
I do have issues with breeders asking people to keep their dog intact so the breeder can have a litter from it if they feel the whim. Esp if the person has no intention on showing the dog. I know a few breeders that do this with people who are planning on competing with their dogs - just in case that person does title the dog they want to ride on the coat tails of that person's success.