Well, for me it's easy cause our stud lives at my parents house.

But they do have a female that they may breed one day, she too young now and smaller than their male still. They keep them separated at ALL times. Either in different rooms of the house or rotate them in and out of crates. They drive them NUTS barking and whining trying to get with each other DAY AND NIGHT. I know it MUST be tempting to want to let them out for 'just a minute' for some peace, but we all know where that would end up...an "accident."
The way we see it, it they never are close enough to have the opportunity, it won't happen. Dog's can get diapers off and mate through fences and will chew through steel to get together. But if they ain't never around each other, it ain't gonna happen!