I'm sorry to hear what you're going through BNL. Intimacy and touch mean a lot to me in a relationship. I really suffer if those are not available.
You have tried therapy, and also many different approaches to talking with him. And there are certain aspects he just does not seem to want to budge on. Can you really live without those things for the next 18 years? Or would it really be a lot fairer on yourself to break this relationship, find yourself again, and thereafter a relationship that can meet some of your needs.
Intimacy is a deep feeling - most of us have that need from the day we are born. It's going to be very hard for you to deprive yourself of it for the next 18 years. And you will land up depressed and frustrated about it. It will not make anyone happy.
I am not going to lecture you, or tell you what to do - these are just my thoughts - as a friend, and as someone who has had to consider similar situations recently