I think you might get more advice/perspectives if you move this thread to a more popular forum (maybe 'our lifestyle discussion'). I think people check that forum more frequently.
I will say that I don't find her behavior "normal" for abdl... There are plenty of us that have heathy sex lives. Sure there are a number of asexual abdl's and some that only appreciate self pleasure, but with anything abdl is a spectrum. There are some that love sex and want it all the time and there are others that don't need it in their life. She seems not to be asexual because she does self pleasure but it is unfair for her to expect you to be deprived. I don't think its fair for a girl to say "guys expect it" and use it as an excuse as to why they don't want to have sex. The reason they don't want to have sex is because they don't want to have sex. Period. If you are in a committed relationship and you think your guy is being too forward it is because you as a girl aren't in the mood/don't want to have sex. If you were in the mood, you would find their advances romantic rather than pushy.... But the digress.
If she isn't asexual and she hasn't been abused (are you quite sure she hasn't been abused? From your description of how she shuts down it seems like she might have been but doesn't want to tell you..) But if these are not the case, have you considered that she is lesbian/transgendered? A good friend of mine had a relationship somewhat similar to yours and she eventually broke up with him after a couple of years. About a year after she broke up with him he came out to her as transgender and he said he found it hard to be with her intimately because she was ashamed of his male parts and jealous of her women parts.. Not sure if this is something that is plausible but you said you were looking for more insight. Hope this helps. Keep us updated.