It could be that you are using iMessage and sending it to your husband AppleID instead of the phone number. Make sure your husband's phone is set to receive iMessages from the AppleID by going to
Settings>>Messages>>iMessage "Send & Receive"
If your husband's email address (Apple ID) is not checked on the phone, then any messages sent to the Apple ID will not be displayed.
Another thing to try , On the husband's iPhone, switch off iMessage. Restart your iPhone and restart iMessage.
