What makes you think you gave him a virus you don't have?
Let's break this down.
Your doctor dismissed your test results (and that was appropriate, given the super low positive you had, the CDC guidelines that say anything below a 3.5 could be a false positive, and you were .3 over the positive range), and you had no symptoms.
Does he have symptoms? What makes you think you gave it to him again?
Keep in mind that there may be a chance you test positive again if you tested with the same type of test. Some people just tend towards getting false positives on the IgG tests. If that happens, you should get a western blot.
It's time to talk to your doctor and/or a therapist about your anxiety. This is undoubtedly stressful, but it's time to talk to someone since you are so panicked by this.