Maybe he is autistic... but is it going to make a difference to how you feel?
There is also another explanation you know... that he's just a f'ing arsehole. Did he even have any logical reasoning for getting you bin bags? Generally autistic people are very blunt and direct with no ability to read between the lines so to speak, but they are logical. So what's the logic with the bin bags? Did you ask?
Also autistic people tend to have a very blinkered set of interests that they are extremely involved in, hence why some of them are very gifted in certain areas.
It sounds to me as though this guy is just getting on with his life and you are a passenger in it, when what you're actually after is someone who shares a life with you, who involves you in their decisions and who wants you to be with them to make memories. This guy isn't that, he's just getting on with whatever he fancies and suiting himself and if you want to pop along with him for the ride then sure whatever.
He won't do anything for you though, he won't give time or hold space for any of your dreams or wants, and I get it, it really really hurts.
I'm guessing you've stuck it out because occasionally he does seem to understand, occasionally he will do something small for you, sometimes it does look like you're winning with him even though the reality is they're just tiny breadcrumbs that you're getting from him.
You get addicted to that feeling of "will I win today" and relationships like this are just basically f'ked up slot machines that you wake up and try to win every day, at some point you realise that years have gone by, you haven't achieved what you wanted to, you haven't gone anywhere you wanted to, you've cried every day/week/month for the last x years and you're just really tired. You're tired of waiting for them to notice you, care about you, consider you and you're tired of being let down.
And honestly if you ain't there now, you'll get there one day if you have any sense of deserving better. If you don't have that sense then please do let this thread be the first step in instilling that back into you!