Certainly an interesting title.
Imagine if you receive a coupon for a cherry pop (soda), went there to get one and get this instead? ...Well, I certainly wouldn't complain.
Ah, I'm certain quite a few of us thought, like him, we'd get to see Megu-neechan get some action...They baited us by pretending we wouldn't be able to see her get any, and then she did, in the end!
...A finger cot, though.
That ending though...! What a chill guy, just show him the coupon and it doesn't count as cheating and he doesn't care anymore. Maybe the husband had a similar experience before...?