Good story. Undetectable does not mean nonexistent. Undetectable simply means that current methodologies do not include a test that is able to detect viral load at very low levels. For one to believe this means the virus is absent, or that it means transmission is not possible, is foolish. It might mean decreased risk, but is does not mean risk free. I have and will continue to discuss my status with a potential partner. If it makes a difference to him, yes it hurts, but it ultimately saves us both a lot of time.
More information about text formats