This was one of the reasons why I wrote one-sided.
He gets sharing points, she gets pleasure and he gets to watch (with help from Diana), which makes him more of a Cuck in my eyes in Swinging Terms he would have a Choice to join in or only watch.
If he does something with Diana he gets cheating points which in my eyes Minus points to Evelyn are.
But I suspect that the dev is preparing an idea to get on the swinging path.
Sharing points and a suitable conversation about what both expect and allow would be enough in my opinion.