It's his responsibility to bring it up, because if he thinks about it, he can relieve Heather from the obsession, and from having to make sure that the affair isn't forgotten, and that in itself begins to restore trust.
Det er hans ansvar at tage emnet op, for husker han at gøre det, kan han befri Heather fra hendes tvangstanker, og ansvaret for at sikre, at affæren ikke glemmes, og det i sig selv er starten på at genskabe tilliden.