Farmer's wives are loyal and hardworking. But men and women's sexual peaks occur at different ages. Yours is long gone. And she's only discovering hers late in life. So many years her sexual urges were repressed out of loyalty to you, and now when her sex is really awakening, yours has already deflated long ago. You probably haven't fucked her properly in 20 years.
Hell, you can't even take care of the farm by yourself anymore. That kind of work is for younger men. Stronger men, men who can keep going, working from dawn to dusk in harvest season. You just sit under the shade tree these days, and watch real men do the work.
Of course, thats one thing you and your beautiful English wife have in common... She's been enjoying watching the men work from a distance. Its only lately that she's come out to the shade tree with you, and offered them cold drinks in the afternoon. Sometimes she can catch glimpses from the porch while you're not home as well. And lately, from her bedroom window.
The men are strong, masculine and hard, but not very well educated. You couldn't afford to hire Englishmen. You went to the immigration office to find your workers for the cheapest price. They're African refugees.
Of course, your wife loved the idea. She's so compassionate. Always ready to help the less fortunate. You never suspected that she was 'interested' in these men. The thought never crossed your mind. Just a simple farmer, oblivious to the finer things in life... you had no idea that her sexual needs were peaking around the same time that she offered to give them English lessons.