No risk for HIV. Anything that was on the dildo would have LONG ago lost its ability to infect. The only danger is bacterial infections, but the sanitizer probably took care of any remaining bacteria. If you have any unusual discharge, see your doctor, but it is NOT HIV.
Tbere may not be risk of HIV but other STI/STD is probable. Though HIV can live outside the body for only a short time other things like hepatitis C can live longer. That is also another blood to blood transfer. With hepatitis it can live outside of the body as long as it is in a liquid that has not dried. I would suggest to you that, because he SAYS “3 weeks” it could’ve been yesterday. You must start taking care to protect yourself.
What you described would be a contact with a external surface, and in 40 years of history, there has never been a single case of HIV infection from a external surface. The only ways HIV is spread are:
-Unprotected anal/vaginal penetrations.
-Sharing needles to inject drugs.
-Mother to child.
All the best.
All the best