Sad day with drug ruined well-heeled suitor (5,5)
I believe the answer is:
sugar daddy
'well-heeled suitor' is the definition.
(rich or well-heeled lover)
'sad day with drug ruined' is the wordplay.
'with' says to put letters next to each other.
'ruined' indicates anagramming the letters.
'sad'+'day'+'drug'='saddaydrug'
'saddaydrug' anagrammed gives 'SUGAR-DADDY'.
(Other definitions for sugar daddy that I've seen before include "(Sweet) older lover?" , "Wealthy older man spending freely on a younger woman" , "Older man lavishing gifts on girl" , "Rich man with a much younger girlfriend" , "munificent elder" .)