I spent all of my time from age 13 up until a year ago in D/s relationships. When I entered a relationship with a 'vanilla' guy, I wasn't sure if it would fulfill the needs I had... But over the years, I understand much about the psychological aspects that underlie such fascinations. Even the ones I may not have, myself.
Being submissive is about being firced to relax, to let go on control & being sure that someone else will take your reigns. Daddy/daughter roles often come from a need for strong nurturing & to have someone to shape your life and/or mind, or to simply be treasured. Even desiring to be hurt or choked has a lot to do with a need for the endorphin rush or to feel powerless, perhaps because you are taking on too much in your "regular" life.
The only things I can suggest are:
1. Out yourself to your boyfriend, because nothing will ever get solved without being honest about your difficulties. If you want to make it easier, say that he arouses you almost to the point of orgasm but you don't think you've had a TRUE orgasm... That way he won't feel inadequate. But once I admitted my proclivities to my current boyfriend/fiancee, I soon found out that I wasn't alone! Granted, I no longer have to subscribe to a role, but if I need something more intense I don't have to feel misunderstood.
2. Really try to reevaluate why you love this person or why you are in a relationship with him. Are you genuinely fulfilled by everything about him, or are there certain things he is not doing for you? Do you possibly feel like he falls short in another area of intimacy to where you cannot orgasm without aid from taboo, which often symbolizes deep psychological needs?
If you find the core & he cannot fulfill that hole (giggity), perhaps you need to consider therapy or another relationship entirely. Perhaps with someone who shares your tastes!! Just be careful, because some Doms or sadists are in it for entirely wrong reasons...
3. Do a sex addiction evaluation. Some people find that when their desires become unrealistic & overcontrolling to where they cannot function in relationships, it is often a sex addiction.