simple ending. You can interpret as you wish. Either the family is stalked by someone else or he just ordered a family protrait and someone delivered:)
There was no reason for jungwoo and jieun to cheat. I understand in case of soo ah when she had children and was rich but jungwoo and jieun were not rich no children they had nothing to fear could have asked their partners to divorce then proceed with their RS
the dad of yul seems sus to, i think he might be beating his wife (kinda possible) that's why she's in the hospital…
Yul's dad thing is confusing. He looks sus but If yul knows something she would have been scared around him but she is not actually uncomfortable around her dad