I'm sure it can still be made fun, like you just walk into the house and start banging her right away while he's still there, he starts watching, Janet saying how much she loves and is addicted to your cock now, talking shit about Adam's "prowess"... Messing her up good, a one man bukkake and leaving him to clean her up.
And it's not like the game would be devoid of fucking wives just under the husbands nose, we get plenty of those already with possibly more to come, it would be just a different flavor to this particular relationship if he were to agree to "share"(more like being a knowing cuck).