Car insurance run through the partner / termination

Hello dear people… and indeed I have the following problem, my car runs through the insurance of the partner at the ADAC, so that I have it cheaper… BUT! I am the HOLDER THIS vehicle! Now my question is if it is possible to get out of there quickly if you want to separate or have separated? In April I came with him to his insurance.. Who has to settle this then, the partner who has the insurance there completely running ? (his and my) Or have also as a keeper the right to cancel the insurance? Because it is my car, it only runs the insurance about him! Would be great if you could help me there somehow or give me tips. I would be very grateful to you