Help!!!!

I have been with my significant other with ADHD for almost 2 years. He recently got back on his meds, so things have been getting a little better. One major issue we have and cannot seem to fix is being intimate together. My spouse has never been in a relationship until we started dating, and has never had any sexual relations with anyone before me. He says he gets major anxiety about doing anything sexual with me and avoids it completely. When we have tried things in the past, he said it doesn't feel the same or it feels weird and he is never able to climax...so now he will come up with excuses like he's tired, not in the mood, just wants to relax, etc. to avoid any type of interaction. We have never had a full (beginning to end) sexual experience with each other. He doesn't have ED or low testosterone. We have gone to doctors, counselors, even a sexual health specialist - nothing has helped. I'm wondering if his anxiety and another person touching him is because of ADHD and if so, if anyone else has any experience on this issue. I am desperate to find out ways to help my spouse. I love him and want to spend the rest of my life with him, but I need to have an intimate relationship and I want children. I feel like I've tried everything to help him become relaxed and comfortable with the idea of sharing intimate experiences together. Please help!