Sorry about your relapse :( Do you mean if your ex cleared the virus could he pass it on to you if you two shared a needle? You said he cleaned the needle so......
Have you ever been tested and when was your ex last tested? If your ex cleared the virus and attained SVR then he should no longer be infectious. The thing is sharing needles is considered a high risk activity.
Your ex could get reinfected with HCV if he engages in a high risk activity that involves HCV such as sharing needles (with someone infected with HCV).
I would get tested since sharing needles can be a dangerous proposition that would wreck my peace of mind.
Well, you have to use clean rinse water and bleach, for all 3 times you rinse(6 different cups), but if he went thru Interferon/Riba treatment before, maybe his Dr taught him how to rinse well, I know my Treatment Doc lectures her patients on the technique.
You might as well just go get tested because I.V. drug use is considered high risk.