"living room(?)" Because in one case the MC is giving something (a gift) to someone of lessor power, so to speak, in order to create indebtedness. The receiver of the gift doesn't necessarily see beyond the gift itself. So, as someone else stated, the receiver is now an ally.
In your case the MC would cause resentment if he cucked (literally by taking the other man's wife; or figuratively by taking his own wife while the man could only watch) the man and rubbed it in his face which would cause resentment. Resentment breeds bitterness; bitterness breeds revenge. No more ally. As is described in Erikson's Malazan series, it's the difference between cold iron and hot iron. Cold iron plays the long game better. Hot iron acts quickly, violently, immediately, brashly...without regard for the long game.
Regardless, I rarely get sucked into these hypotheticals, but the "mental gymnastics" are sometimes good exercise. Thanks.