Can I reinfect my partner if I am not on meds?
If my partner is positive and on medication could I reinfect her and I am not on meds?
Will her viral load keep going down if she continues to take her meds?
The quick answer is that everything will probably be fine.
If your were partner before you were both diagnosed, you are likely to have the same virus, so reinfection will not be a problem.
It would only be a risk if you have drug resistant HIV, perhaps because you were infected afterwards or because you used treatment before that failed. If either of these situations are likely, there is a risk that reinfection might b with drug resistant HIV.
Is there a reason why you are not on treatment yourself?