When should you tell your boyfriend/girlfriend you have asperger's?

That may be, but just simply ignoring or refusing to discuss some things probably make them feel like you are hiding something or are not trustworthy.

"Sorry I have Asperger's and some topics are difficult for me to discuss. It has gotten better as I have worked at it and have gotten older. I hope you'll understand." You don't need to tell how terrible your school experience was right then, just a simple explanation. If a girl scares off that easily, the relationship would not have lasted anyway. We all have issues we are trying to work past and it is just finding the right person.

I have a friend with Asperger's and is face blind (she can not recognize people by just their facial features) but she is happily married with two kids. You just gotta find some that is "your kind of crazy".

If anyone treats you like that school did, then they are terrible people who don't deserve your time.

My advice to all people is that their life experience help shape (but not define) their self. If you are happy with who you are, then embrace your past experiences.