IDK about your's but where I live(not in Korea) they would beat your ass 3 times if you get caught. 1 from the teacher 1 from the principal or guidance councilor and 1 from you parents. So 3-4 times. 2 if you're lucky.
1. Her reputation is shit
2. She's the wife meaning she has less rights/authority than her husband. (This is based on the law at the time).
3. There's a possibility that her husband's cheating.