Most middle-aged couples in Japan tend to express their dissatisfaction with their spouse.
ーMany married people complain about their spouses.
「多くの既婚者は配偶者の不平を言う」
married people で「既婚者」
to complain about で「〜について不平を言う」
spouse で「配偶者」
ーMost middle-aged couples in Japan tend to express their dissatisfaction with their spouse.
「たいていの日本人の熟年夫婦は配偶者への不満を漏らす」
middle-aged couples で「熟年夫婦」
to express one's dissatisfaction with ... で「…の不満を漏らす」
ご参考まで！
カナダ 
