Sounds to me like he got comfortable around you and trusts that you are clean. Without a medical report, I don't understand looking at a person in the face and trusting that they are “clean”. These diseases aren't written on the forehead. However, the type of life you lead makes it easier to believe you're clean. This guy stopped using a condom with you because you let him take them off the first few times and it just felt like you were cool with it because he is.