When is masturbation for a married man forbidden in the mentioned cases, such as exciting his wife, or with her help, or before intercourse, or while fondling his wife during menstruation, or if the husband ejaculates before satisfying his wife?

Masturbation is forbidden (haram), and it is even more forbidden for married individuals, whether done in the presence or absence of the spouse, and whether requested or not. However, there is no harm in the husband masturbating with his wife's hand or engaging in thigh intercourse with her, due to Allah's saying: "And those who guard their private parts. Except from their wives or those their right hands possess, for indeed, they are not to be blamed." Similarly, there is no objection to either spouse stimulating themselves with their hand before intercourse, as long as ejaculation is not intended. As for the wife completing the act of intercourse with her hand after the husband's ejaculation, this is forbidden. However, her husband may do so for her until she satisfies her desire.