Noona-romance for the win! (drama version)

Main couple: age gap 17 years (45/28)
Background couple: age gap 14 years (40/26)

Main couple age gap: 4 years (30/26)

Main couple age gap: around 7 years (32/25(?))

Main couple age gap: 18 years (43/25)

Main couple age gap: 14 years (33/19)

Main couple age gap: 8 years (33/25)

Main couple age gap: 5 years (33/28) /they had an affair 10 years earlier/

Main couple age gap: 15 years (38/23)

Main couple age gap: 6 years (36/30)

Main couple age gap: 12 years (31/19)

Main couple age gap: 6 years (29/23)

Main couple age gap: around 15 years (40?/25?)

Background couple: age gap around 25 years (60?/35?)

Main couple age gap: 4 years (23/19)

Main couple age gap: around 4 years (30(?)/26)

Main couple age gap: 6 years (34/28)

Main couple age gap: around 5 years (?) (33?/28?) The ages are my guess based on other characters' ages.

Secondary couple age gap: around 20 years (45?/23?)

/I don't think their ages were clearly stated. The guy graduates from a university near the end of the drama and a woman is a mother of FL. /

Main couple age gap: 4 years (27/23)

Main couple age gap: 10 years (30/20)

Main couple age gap: 10 years (35/25)

Main couple age gap: I think it's around 4-5 years  (25/21)

Main couple age gap: around 5 years (I don't know how old is Su Ban Xia)  (27?/22)

Main couple age gap: 8 years (33/25)

Main couple age gap: around 10 years(?) (32/22)

Main couple age gap: 13 years (35/22)

Main couple age gap: 6 years (38/32)

Main couple age gap: 5 years (23/18)

Main couple age gap: around 4 years (28/24)

Main couple age gap: 16 years (34/18)

Main couple age gap: 15 years (35/20)

Main couple age gap: 12 years (30/18)

Main couple age gap: 3 years (32/29)

/They're making a lot of fuss about their age gap, even though it's just 3 years. /

Main couple age gap: 10 years (35/25)

Main couple age gap: 10 years (38(?)/28(?)). The ages weren't explicitly stated, but she has a 17-year-old daughter.

Main couple age gap: 10 years (32/22)

Main couple age gap: 10 years (30/20)

Main couple age gap: around 5(?) years (30(?)/25(?))

Main couple age gap: around 10 years (36/26(?))

Main couple age gap: 7 years (31/24)

Main couple age gap:  around 4-5 years (?) The ages were not explicitly stated, but my estimation is 30/25.

Main couple age gap: 7 years (25/18)

Main couple age gap: 3 years (28/25)

Main couple age gap: around 4 years (30/26?)

Main couple age gap: around 5 years (30?/25?)

Main couple age gap: 13 years (35/22)

Main couple age gap: 6 years (28/22)

Main couple age gap: at least 15 years (40+/25?)

Main couple age gap: 5 years (37/32)

Main couple age gap: 10 years (34/24)