What is the ruling on a husband fondling his wife in Ramadan until semen is discharged, given the existence of a legitimate Shari excuse that permits breaking the fast?

A wife is not permitted to allow her husband to enjoy her while she is fasting. However, if she does so, her fast is not invalidated except by intercourse or ejaculation. If she only experiences pre-ejaculatory fluid (madhy), there is a difference of opinion, and it is more prudent for her to make up that day's fast.