I have asked myself these questions hundreds if not thousands of times. At twisted as it sounds, I wanted to think that I was selected because I was special. The truth is, I was available. I was in the wrong place at the right time (for him). Any ideas that I was special is only my mind trying to find some justification for it so it doesn't hurt so bad. I don't want to think of myself as a piece of meat, I want to reinterpret things to make myself important, when, in actuality, I was just a piece of meat.
It's hard to come to terms with the idea that it was pleasurable or that you liked it. I felt the same way. It simply a physiological response to stimuli. Our bodies are designed to react in a specific matter when stimulated manually, and that's all that it was. It doesn't mean that you liked the situation or that you liked what was happening to you. Any thoughts that you have about it are higher order thought processes interpreting an involuntary reaction. Please don't beat yourself up over this when you had no choice.
Remember that you were a child when the abuse occurred. You are no looking at it from the perspective of an adult and interpreting the situation as an adult, when in reality, the child that you were was not capable of seeking it out, or putting yourself out there as a means to protect your family. It is again, your adult self looking for ways to interpret the situation so as to make it less painful and traumatic. You survived and you should be proud to the strength you possess that enabled you to make it. The idea that you protected your family is a noble deed and you may in fact have done that, whether a conscious decision on your part or not. Sacrificing yourself doesn't mean that your life is less valuable than your family's. Please believe that.
He did not love you. Love is gentle, love is kind. Love does not destroy. He twisted a beautiful emotion in order to put you under his spell. Please don't mistake his actions as something wonderful, because they weren't.
I often think that the fact that my perps picked me enabled my brothers to escape his dirty deeds. I feel I somehow saved them from something awful and thus allowed them to fulfill their purpose in life. I felt that I was sacrificed so they could achieve greatness. It may make for a great story, but it's not true. I, like you, was simply around.
I wish you well Nolan. You are a beautiful person with much to offer and much living to do. I hope you find healing and I wish you well.