I know some of us are really self-conscious and haven't quite gotten there with accepting themselves. However, for those that have, and can have some humility and humor about themselves, a bit of light-hearted humor might be good.
I only get a bit irritated with false stereotypes and derogatory statements, then I will give you "the business".
Your life partner needs to know these things, for better or worse. He's liked and accepted you so far, and this may be the introduction to the conversation, and your autism, in no way, affects that.
I wasn't diagnosed until 30 years into my marriage. I was relieved and happy for the diagnosis, but my wife couldn't wrap it around her brain for over a year. It really had to settle in. For her, it was never an epiphany, an "Ah ha, that makes sense." sort of thought. She really had to take the time to learn on her own what autism was, versus the stereotypes we both grew up with.
I think the public has a good understanding of what autism may present like in the severely affected small child, but the media really doesn't focus upon how it may present in a teenager, an adult, or an elderly person, especially if they also have a higher intellect and executive functioning. It simply gets passed off as "something else" and autism isn't even on their radar.