Oh, post script: having been learning a lot about myself and others here, I have come to the conclusion that he is a sub. I won't go into the details of why I believe this, but I am firmly convinced of it. It is therefore impossible for us to reach compatibility since I am principally a sub.

Have you considered this as a possiblity within your relationship? He might be battling very hard against what he thinks of as 'unnatural urges'. That wouldn't help you to resolve your sexual situation, but it might help him to find out what fulfils him, and you might at least end up with two people who have found and accepted their natural inclination and are happy with it.

Probably not very helpful... sorry.