As it seems your starting to figure out, he has some deep issues, even outside of the religion. I dont even think he fully understand what he wants, which is scary. He seems delusional.
So now its not about the sex, or being your boyfriend, he just wants to be bff's for life. So what happens to you all's friendship when he finds a suitable JW mate?
Once he is baptized, your friendship will be frowned upon because you are considered "wordly", and that's a no no, especially with the opposite sex.
What happened to make him fall out of love with his ex girlfriend of 5 years? And it seems he was hurt because they didn't remain friends?? Well that's not realistic...in the real world there are no guarantees that you will remain friends with your ex.
Another thing, I have a family member that's not baptized and dating a non JW. He respects her and is not expecting her to convert in order for their relationship to move forward. He stop practicing the JW religion (probably because he knows he not following JW rules at the moment), I'm not sure if he'll return if they get married. But the point is he seems to see things for what they are and they both respect each other's religious preference.
Your guy is already pushing the boundaries of the religion...he could very well move forward with you and even eventually marry you (it would be frowned upon like every other thing he is doing, but he wouldn't be the first or last to have done this) but it seems for whatever reason it's not worth it for him. He's definitely coming off unbalanced... start backing away.