Dont know best way walk away from this ?

Most of us on this planet are not raised in the best situations, nor with ideal parents. We might experience a lack of parenting and no one helping us into adulthood. So by the time we're biologically read to have children and find a mate, we're far from ready emotionally or psychologically. 

It sounds to me as though she encountered something genuine and loyal in you which made you attractive to her.

But slowly realised that there's something missing in the connexion (like most NT / Autistic relationships). She misunderstood this lack of connexion for lack of interest. Or misunderstood this difficulty relating with you as a type of Rejection. And perhaps, like most Neurotic (NT) individuals misunderstood this as "Mystery" or a NeuroTypical game of hide and seek. Some NeuroTypical men are actually taught to be dismissive, cold and cruel to NT women as a way to make them dependant or as a mind-game which apparently encourages desire and intrigue. I find it disgusting, but apparently, there's a pay off as one rule is that you have to give them a reward occasionally, much like training a dog. Women play games too, so I guess maybe that neurotype can get bored easy, who knows.

Autistics don't operate like this. 

What's happened is she has mistaken who you are and wouldn't be able to understand without an autistic female friend. But what happens is resentment builds. And over time, that takes a toll on health.

For your sake and hers, everyone should have some breathing space. And if you want to break up, just tell her direct. You can say something as simple as I care about you but this doesn't work for either of us. 

Don't   think she has anyone that could be there  only one friend that I know of not sure even if he Was there how things would go.

She had said if need break from things stay family for while then

Other  times she feel like need me there do everything for her

The best way is the way you suggested. If she doesn’t live with you, text her. Cut all contact.

From what you have said, your girlfriend is a drain on your emotions. She is possessive and toxic. She is trying ti control you, say who you can and can’t see, and is trying to separate you from your family. What ever is going on with her ex is anyones guess! Leave her to him! You can and will do much better. 
But for now, be good to yourself. Eat well, exercise and do things that make you feel good.

Blimey mate - you are dealing with a lot!

For what it is worth, I believe that a person who tries to stop you being in healthy contact with your own family is BAD, BAD news for you.  That is the red flag that flaps most loudly.

If your gf is bed bound and suffering from serious health problems, PLEASE don't dump her by text!  Get yourself mentally prepared to explain yourself to her in person and try to be as kind as possible - maybe have someone organised to come over when you have finished talking so that whe is not left alone afterwards.

This experience, bad though it sounds, will make you stronger and more wise in the long run.

Stay sane & good luck.

Never heard that before just always feel confused by it 

Oh boy. It sounded so much like my ex-partner. after 5 years renting with flatmates we rented on our own, since then it all went downside, like what you were writing, 

your gf doesn't want you to contact your family, or talk about your relationship with them,  so they did not smell something off and tell you

it is gaslighting toxic relationship, where autistic is being used and stays non the wiser

my ex had romance around 6th year together

since then we never did do anything together or go out together

from 8th year we've been just shouting at each other and quarelling, so I started to avoid her, and we had quiet days

she told me once in anger: ''I did not sign for a fu..ing asperger''

then during 10th year we promised our friends to come to their new year's eve party, on a way there she announced me that she has a new boyfriend and that she is moving out

end of story