Should the sex scene surprise the observer? Then porn would have died out as a genre long ago. Considering that it is possible to go the way where Sofia has not had sex with her husband for a long time (or with someone else, heh) and if this scene is most likely later than Aiden's task, then she already has some excitement and a tendency to lust. After all, now tasks bring not only anger, but also excitement. And it is no longer so important threesome, classic, masturbation - the process of arousal will still go on. Of course, she will not be "real horny", but a playful little hand will find a place for itself.