色事は思案の外

いろごとはしあんのほか

love and reason do not go together

思案

しあん

thought, consideration, deliberation, reflection, rumination, pondering

案外

あんがい

unexpectedly

思案顔

しあんがお

pensive (or worried) look on one's face

思いの外

おもいのほか

surprising, unexpected

虚仮の後思案

こけのあとじあん

hindsight is 20-20 (even for a fool)

思案投首

しあんなげくび

being at one's wit's end, being (quite) at a loss (what to do)

鼻元思案

はなもとじあん はなもとしあん

superficial (shortsighted) way of thinking, half-baked (foolish, ill-advised) idea

鼻先思案

はなさきじあん はなさきしあん

superficial (shortsighted) way of thinking, half-baked (foolish, ill-advised) idea

喉元思案

のどもとじあん

superficial (shortsighted) way of thinking, half-baked (foolish, ill-advised) idea

恋は闇

こいはやみ

love is blind

恋はデジャブ

こいはデジャブ

Groundhog Day (1993 film)

思案に余る

しあんにあまる

to be at wit's end, to be at a loss for what to do

排外思想

はいがいしそう

anti-foreign sentiment, xenophobia, exclusionism, exclusivism

此処が思案のし所

ここがしあんのしどころ

This is the point we need to think about

恋恋

れんれん

attached to

恋は盲目

こいはもうもく

love is blind

恋の闇

こいのやみ

losing one's reason due to love, lack of judgment due to love

恋の病

こいのやまい

lovesickness