Good god no, PLEASE don't let her have a litter. Reasons against:
Biggest one - HUNDREDS of healthy dogs are already killed EACH WEEK in pounds up and down the country purely for want of homes. Staffies make up the greatest number of these, owing to public prejudice and undeserved bad press. If your DH doesn't believe me call your local council, ask where their pound is and take him there and show him the dogs who will be dead the next week. SOME pounds do their best to rehome, some don't even try for Staffs and other hard to home dogs (yes I'm talking about YOU, Fleet Kennels in Yorkshire). Breeding yet more Staffies just adds to this heartwrenching burden.
Rescue does its best to step in and take as many of these dogs as possible into safety and rehome them but they cannot more than a fraction of those who need it. The rest die. If a person wants a dog, Staffie or otherwise, pup or adult, rescue has thousands patiently waiting for homes. Breeding more lessens the chances of rescue dogs getting a home and therefore they are taking up rescue spaces which could be offered to the pound dogs. This is especially true since the RSPCA decided not to accept unwanted dogs from the public and so independent, unfunded rescues have had to take up that burden too.
Add to that the cost to you if your SBT needs a section or vet treatment as a result of pregnancy or labour. The cost of feeding and vaccinating pups. Not to mention the stress, the having to have someone at home 24/7 to care for them for weeks and months, the mess and the worry about keeping pups and DC seperate. Plus think about the search for homes - good ones - and think of how you will ensure that they are good. Ask yourself what you'd do if the new owners can't keep the pups, now or in 10 years time and they are only able to have the dog/s put to sleep. Can you take them back? A good breeder will. A good breeder only breeds pedigree, KC reg dogs to improve breed lines and when they have vetted homes lined up BEFORE mating and when they know they can take any or all of the dogs back at any stage of their lives should the owners not be able to keep them.
Spaying will also reduce the likelihood of many problems, result in a calmer dog and avoid illnesses such as certain cancers as well as reducing possible aggressive tendencies.
PLEASE PLEASE don't do it. If your DH is still in doubt let me know and I'll show him some of the appeals I have for dogs who need rescue spaces and who will die in the pound if they don't get them, let us rescuers show him the photos of the healthy young dogs we have tried to save and who never made it.