Because sex is a physical need but satisfaction of sex is triggered from your mental connection with the girl and not just ejaculation.
During bar visits over the time one naturally get acquainted with the girl's face , voice appearance becomes familiar to you then the relationship builds and it reaches that stage where the last / climax act or the deed takes place .
Only if this cycle is followed then only one can get the satisfaction as the person is not deprived of sex but of good company who will not cling to him or would not ask for alimony if he breaks up suddenly with her .
This cycle of friendship - relationship - physical relationship is to be followed in this sequence only . Otherwise, if you are are just physically attracted to a girl even if she is good in bed one will not get the real peace of mind or satisfaction even if you fuck her full night one will still think that something is missing.
Hence the majority of bar mongers find it difficult to leave the DB world , they can get the respect , priority ( which might just be an act ) from the girl's side.
Also he can make her his Daasi / slave as he always feels superior to her as she dances for him or while he throws the money . The male ego is boosted and only satisfied at the end when his true requirement / hidden agenda is fulfilled which is entering her love

hole
My 2 cents . Pls correct me if wrong .
Cheers
Sent from my Iphone