Is distress or sadness caused by a beloved friend in Allah who performed a permissible act considered ungratefulness towards the spouse, even while not forgetting his kindness or uttering anything that indicates denial of his good deeds?

"Kufran al-asheeri" (ingratitude towards one's companion) means denying a blessing, disavowing it, or concealing it by not expressing gratitude for it. This concept is not exclusive to a wife; rather, it applies to anyone who has received kindness or a favor from another person. As for your feeling of distress towards your friend, it is not considered "kufran al-asheeri," for everyone has their own peculiarities and temperament. It is part of good companionship to conceal your sadness from your friend and to show him contentment.