Partner has ASD....what am I to him?

I have only posted once before and appreciated the responses I got. I feel like I can turn to the community again for some help as I feel so pressured and confused and I genuinely feel like I’m slowly going insane. My partner has asd, not officially diagnosed yet as still on waiting list. But he has it and very aware that he has it. We have been together a couple of years, he’s in his early 30’s and since being with me has come to realise he has asd. He started out by telling me that he loved me early on and giving me affection and reining it from me happily. I noticed he wasn’t very verbal and say any kind of feelings or most chat via text. Since then I have learnt that he doesn’t like giving affection, I’m not sure how he feels about getting it because he says different things which confuses me. I generally don’t know where I stand with him. What is my purpose? He tends to do things with or for me as a tick box exercise not because he wants to. He says he struggles to talk about his feelings....yet if he wants sex all of a sudden he is then able to tell me his feelings- all be it limited but is capable. I can’t understand. I feel like even though we have built a life together and have made some commitments, he only actually sees me as a person who is there for his own sexual needs. I feel on a massive rollercoaster where I’m up and down and I don’t feel he’s completely honest with me and when I stupidly bring it up he says very hurtful things when I just need to know where I stand. I’m a very loving person and I crave quality time with him- this is rare as we have children from previous relationships that live with us. I genuinely feel that if I died tomorrow he wouldn’t care or feel a thing. I love him so much and want him to feel the same way about me too but I don’t think he can or does. I don’t know if his love is different to mine and when he says he loves me it’s different to how I love him at a ‘neurotypical’ person. I think about him when he’s not with me I care about him I want time with him I want to talk him and show him I love him. I fear he doesn’t feel or have any of this for me which leads me to such confusion as to why he’s with me still. He’s a good person and helps around the house and spends some do his time with me. But is it because he wants to? Is it because it’s what he thinks it’s what’s expected? Or is he doing it because  he wants to have sex. He can tell me he loves me and say a nice thing if he wants sex but not really any other time. I don’t want to feel used in this way. Can anyone please help as I get no answers from him just answers and I have no idea how to understand him as he says a lot of contradictions. I appreciate any help as I feel like I’m going mad and I’m going to fall apart soon. 
Thankyou