To me this guy sounds pretty unstable. I believe in the general good of all people and I'm sure he's a good person underneath it, but right now it sounds like he's wrestling with so many personal issues that there's no way you can have a healthy relationship with him. I would guess he has low self esteem and that's why he's been sexually promiscuous (to fuel his ego) and that's why he bounces between being really egotistical and self-loathing. I would not stay involved with somebody like this. If you really want to have a relationship with him, yes the test results and honesty would be important to pursue. But it doesn't sound like he's ready to have a mature relationship.