What is the ruling on a wife pleasuring her husband remotely using a device controlled by the wife from afar, which leads to the husband's ejaculation, due to work circumstances that require being away from the wife for periods?

It is permissible to ejaculate by looking at one's wife, or her picture, or by speaking with her, while taking caution that no one else sees the conversation or pictures. As for ejaculating by masturbating with the hand or with anything other than the wife's body, it is forbidden.