Divorced 33 years ago:
Yoo Dong Gu (60) <------> Shim Jung Ae (59)
Children:
Yoo Eun Ah (38)
Yoo Eun Hyuk (36)

Married:
Yoo Dong Gu <-------> Go Chun Young (57)
Children:
Yoo Eun Sung (28)

Married:
Kang Ki Seok (widower - 59) <-----> Shim Jung Ae
Children:
Kang Seon Woo - (35 - ep 104 has SW stating he is 35, a year younger than EH - who is now 36 - must have had a birthday off screen))   (ep 51 - JA is asked how old SW is and she says 34);  Ki Seok’s son from previous marriage;  Jung Ae’s step-son
Kang Seon Joo (28) 

Eloped 30 years ago?

Shim Jung Seok (49) (Jung Ae's sister) <-------> ?? Tae Ho

Married:
Shin Dal Yong (80) <——-> ?? (Evidently, according to KBS site, grandpa has been married and divorced multiple times. His children are half-siblings - different mothers)
Children:
Shin Ha Sung (deceased)
Shin Ha Young (30)

Married:
Maeng Jin Sil (58) <——> Shin Ha Sung (deceased)
Children:
Shin Min Guk


Grandchildren:
Shin Ga Ram

Not Married but had a child:
Shin Min Guk (34) <———> Hye Young  (grifter; abandoned GR as a baby with MG and didn’t come back for 6 years)
Children:
Shin Ga Ram (6) 

Potential Couples:

Kang Seon Woo  <----> Yoo Eun Sung

Yoo Eun Hyuk <----> Shin Ha Young

Shin Min Guk <----> Kang Seon Ju or Yoo Eun A ??

Shin Dal Young <----> Shim Jung Seok ??