Did she add you to the ADR when she booked it? If she didn't then she can just go into the ADR from her account and add you. I never add my husband when I book ADRs, I just make an ADR for two people with myself as the lead guest. On the rare occasion that he is curious about what we are doing I just go into the ADR and add him so that it shows up in his plans too. Not sure if there is any other way to do it without her specifically adding you from her account on each ADR.