False negative and psychology of risk.

SHould I worry about the possible false negative beyond six month?
It would seems so at least psychologically.
My reason is as follows
The sensitivity of the test if 99.6%
That means, chance false negative is about 4/1000
Risk for per unprotected anal sex  is about 5/1000
(Assuming the true hiv status in each case is undertermined, meaning  its probability is approximately as the prevalence rate in general population)
These two seems comparable
However, the later is deemed to be risky, the former isn't seen as an issue

[peekawho]

If you have a negative result at 6 months, that is undeniably conclusive and can be trusted.  

[Hao]

To peekawho.
thanks for the reply

sorry about the lousy English in my post, i am losing my English recently

when i am in a very bad mood, my brain tends to regress into a low-functioning level, in which i am less able to process the foreign language...english for me, which is radically different from my mother tongue, which is Chinese