Most of the tests are more than 98% sensitive and specific. If it is negative after 3 months you are unlikely to have HIV. But to be more specific, try to have one more different type of rapid HIV test
or Western blot. If it also remains nonreactive then you need not worry at all. Her symptoms of rashes fever
may be due to some other reasons, likewise your flu
like symptoms of flu, cold
,, rashes also may be due to something else.
Even if she is having HIV disease, there are many chances of being uninfected. Many couples remain sero-discordant in spite of many years of continued sex contact.
So you need not worry.