I can’t say whether you should or shouldn’t confront your partner on the positive test strips. What I know has helped me is speaking to a counsellor about what I’ve gone and am going through. They allowed me to talk openly and helped reflect back to me that the other person’s behaviour is not of my doing. I also needed to take care of me and heal myself.
Maybe talk to someone independent of your situation who will give your better guidance, than well intentioned friends and family could. My main advice is do all you can to protect yourself from any more mental harm and anguish that the other person is inflicting on you. It’s hard wrestling between head and heart, just know you are worth more than being treated in such a cruel way.