交際 こうさい
kōsai

Noun
Suru Verb

1. company; friendship; association; society; acquaintance

Intransitive
その おとこ つま交際 こうさい はじめた。
sono otokowa tsumato kōsai shihajimeta.
The man took up with his wife.
Noun
Suru Verb

2. (romantic) involvement; dating

Intransitive