Hi, i’m not sure if this will be helpful at all but out of all the people i personally know who have had covid, not one of them has spread it to their partner. i’m really interested in, when this is all over, learning about how this thing spreads because i feel like there is some factor that explains that. most people and their parents that i know took the same precautions that you and your gf are taking, and it seems like those precautions work. i would get tested again in a day or two and then rest knowing that after that point, your risk for getting it from her has gone down significantly because she was most contagious in those first few days and now you are taking extra precautions.