If no one eats nuts, we'll all (eventually) be overwhelmed by ever-growing piles of uneaten nuts. Then people with but allergies will really be in trouble.
Therefore anyone who can safely eat nuts has a moral obligation to do so. q.e.d.
Should you fuck your wife? Well if we were to universalize this act, I would be fucking your wife too, so given that you don't have a cuckold fetish you should refrain from doing that. Unless...? 👀