1 saved contact is coming up in sms as number not the saved contact name?

the contact that i use the most (my partner!) i received an sms yesterday after landing from the UAE and it is only showing his number< so i went in an addded as exisiting contact thinking this would rectify it....it didnt, i did a new contact but that didnt work so now i am at a loss as to why..as other peoples messages are coming through with their names on...can anyone help!!!