Dated after fling husband overlooked? He's been betrayed (7)

I believe the answer is:

cuckold

I'm a little stuck... Click here to teach me more about this clue!

'dated after fling husband' is the definition.
'cuckold' can be an answer for 'husband' (cuckold is a kind of husband). I am not sure about the 'dated after fling' bit.

I don't understand the remainder of the clue.

Can you help me to learn more?

(Other definitions for cuckold that I've seen before include "Man married to an adulteress" , "Man whose wife has been adulterous" , "cheat on hubbies" , "Man cheated on by his wife" , "One cheated" .)

I've seen this clue in The Independent.

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