My boyfriend is similarly awkward in his sexual behaviour. I left my Ex for him and didn't expect what was coming so i was pretty disappointed as well. Turned out he was socially very detached all his life and hid this from me. At first i just complained, don't do X i don't like it, but he didn't stop either and was like "but this is what i like" but he had sexual problems regardless, so after i while i dug deeper and it turned out that he just didn't understand human closeness, bonding and sexuality. By that i don't mean my preference, i am fairly experienced and tolerant and understanding to most sexual needs and ways, including dominance and submission, but he was somehow off. He was all alone in his life, an outsider and in an all boys school. So he had developed strange sexual concepts, based on porn but minus the humanity of the people involved in a way. Examples are, he would growl a lot, breath deeply, say certain creepy things and moan weirdly (like an overdramatic bad female actor) while not having an erection and losing momentum and joy? as soon as things got more heated. I knew it was just off, he didn't enjoy what he did but somehow could enjoy other things even less. Anyways, i pushed for it, it was painful, and he often didn't want to deal with the problem but i made us deal with it. I knew there was a way for both of us to be happy, if i just knew why and how he liked something and for that he needed to know first himself. So we've read a lot about the topic, fought a lot, cried a lot, laughed a lot and were glad over our discoveries. Now we're happy most times. It was mainly insecurity and detachment, lack of general empathy and seeing me and others as "human beings". I guess what happens if you grow up without family and friends in a hostile environment. But let me tell you, it was hard. And if he didn't love me so much and wasn't as determined to be a good partner and go through this journey we wouldn't be where we are. Preference is not just preference in our complicated times and there is a lot of resources available for better handling and understanding. We don't want to limit people and make them feel bad for their sexuality but sometimes that keeps us from understanding and recognizing issues. Sexuality can have issues too, like any other aspect of ones emotional life.