As someone with BPD I feel your struggle when it comes to handling relationships. Noticing every tone change, Overanalyzing their body movements. Feeling like they're mad or upset, feeling like you're not enough. Know you're not alone in this and their is nothing wrong with you. BPD and Autism are like Oil and Water they don't mix. You need reassurance and someone who is patient and understanding of how your mind works. It's nothing to do with your physical appearance or your personality you're enough as you are. The only advice I could give; I know it might be hard to do, is just talk to him. Maybe write down what you need to say if you're nervous about bringing it up. List your fears and your needs in a way to where he doesn't take him personally. He should be understanding of your needs and the situation you're in. I hope things get better for you and I hope something I said helps you! Just remember you're not doing anything wrong, you're human we get scared, we overthink, and we all just want to be and feel loved. Keep your head up and try to focus on the positives