I agree. Even more, I don't understand why the wife of the main character, who must be very smart for a researcher, can't understand the reason for cheating, in which the main character has no choice. Either she is just stupid (because the author did not think about this moment) or she herself is involved in this "random" story with getting to the island, because she purely accidentally fit in very well with the team.
I think it is highly likely that they were specifically targeted. it isn't clear yet whether the wife knew about it beforehand.
Personally, my only real criticism of the story so far is that it relies too much on the husband and wife not communicating.
He hasn't told her about how he was forced to do things, or the things he saw and his fears, etc. And he is being rude and abrasive towards her. This is realistic to some extent, but when stories consistently rely on conflict to happen because of lack of communication, I always get a bit frustrated with them.
I think its clear their relationship is about to experience some changes and the couple will go through an awakening. But hopefully there aren't any weird/abrupt personality shifts incoming, like in Moving Down. And I also hope that there is still an option for them to stay romantically involved.