I am very sorry for the pickle you have landed in! Pet shops are notorious for the bad information they give - all they want is a sale, not animal welfare! We sadly get quite a number of new members coming here because of a problem due to a pet shop.
Your options:
You can either find each of them a friend of their own sex; that would probably make your wife happiest. if you are short on space, you can either stack the cages on top of each other, or for easier access, have the boar cage on a cheap or secondhand table above the sow cage. Boars and sows should not be able to see each other because the pheromones of a sow coming into season can cause fights in hormonal boars.
Or you can take one of the piggies back and get a same gender friend for the other. If you prefer to rehome privately, please don't leta piggy go into a single situation and make sure that their new home a decent standard of care. Guinea pigs are social animals that shouldn't be kept with a companion of their own kind. (Another welfare issue that pet shops ignore!)
Have a look at the information threads at the top of our Care sections before you rush out to buy more cages etc. A big cardboard box will do as a spare cage for a few days while you decide what best to do and where to best source any stuff from. You are welcome to ask any questions you may have.
Which country are you in? There are rescues and shelters in Britain, Australia, the US and Canada. Here in Britain, we strongly recommend to have your single guinea pig bonded under expert supervision at one of our recomemnded good standard rescues, so you only come home with only guaranteed character compatible, healthy and non-pregnant piggies. Some rescues in the US will also offer meet&greet sessions, which make for a much more stable bond.
You can add your country, state (US/Aus) or county/general area (UK) by clicking on your username on the top bar, then going to personal details/location. That would be a great help for us in giving you any appropriate advice and recommendations straight away.