[h2oot]

My follow-up thoughts are these:

If you and he dont have a romanticl/love-based relationship with some deeper feelings I doubt if he would get tested. There are two reasons for him to get tested 1) one he loves you and wants to show his respect for you by making sure he is clean or 2) its a price he has to pay for some sex. In the first instance you may have a chance, while in the latter forget it.

I may sound like Dr. Phil here, but your use of the word dirty implies that there is something really repulsive to you about his past behavior. Maybe more than the possibility of STD. If that is true you may want to rethink why you want to do this.

About his reputation, I would go with what you feel. Its you that has to deal with the consequences and whether you can get past your opinions of him and what you think of yourself if you do have that relationship. Maybe I am wrong but I think you have more feelings than just your fear of STD.