I would say that with your acceptance and tolerance of him already already provides you with an advantage. I personally haven't had a relationship last all that long, but I believe it's definitely sustainable at some point. I must agree with atypical that the process you listed fits best with narcissistic personalities. However, narcissistic tendencies are often found in those with aspd.

Interestingly enough my longest relationship was with a Girl with a b cluster personality disorder. Perhaps there's something to that.