I do not think that your taking Duovir would have affected your HIV ELISA result. False positive results are not infrequent with ELISA and Rapid/Spot tests and that is the reason that we always advise more than one test. I would advise the following:
1. Please do not take any anti-retroviral drug unless you have a definite diagnosis of HIV infection and your CD4 count has come below 200 or AIDS defining illness occurs. These drugs cause resistance in the virus very fast, especially if not taken regularly. If that happens they will not be effective if you should ever need them.
2. Get another ELISA test done after an interval. Even if infection has occurred, it takes a while for the antibody tests such as ELISA to give a positive result. This time is generally about 12 weeks but can be longer.
3. Continue to use a condom and practice safer sex. Even if you are both infected, a condom is required because re-infection makes the condition worse.
4. Continue to support your wife in all ways as you are doing. She needs you at this time.