Thanks for your question and concern. As you may know, genital herpes is an infection caused by virus and specifically Herpes Simplex Virus. There are chances to get infected with the virus from an infected person through skin to skin contact. The primary reason of getting infected is through sexual intercourse with infected people. But sharing of toilet also can be risky. It depends on the state of infection in her. Is she is having an outbreak of the infection and is having blisters, it is necessary to clean toilet seat thoroughly before using it, after her use. Also educate her to be hygienic and wash her hands after using toilet. Avoid using her towels. Anyway, drinking and eating along with her potentially will not make any difference. Just avoid direct contact with sores and blisters that she may have. After the outbreak ends, you can behave more closer but keep hygienic practices as before. Anyway there is no way to treat herpes so that the virus will be entirely eradicated. So, keep yourself out of direct skin to skin contact with infected one. Hope my answer helps. Take care.