If i love her why do i use her

When I was 8 years old my mother remarried a man, I was happy as we were kinda poor living in Detroit MI, my father had left us before I could really even remember him. My mother tried to do the best she could raising me, but it never seemed enough, so I was really happy to have a father in my life, he was a cool guy for an adult and he had a good job. He took us out of Detroit and moved us in with him in a nice suburb
My mother and step father had a child, my step sister Faith, less than 9 months later, as an adult I realized now that my mother was pregnant before she got married. We grew up pretty normal, not rich but upper middle class. The only thing was my mother was extremely controlling, didn’t allow me to do much, but I did play football starting when I was in 7th grade, I had a lot of friends and Faith became my little buddy. She adored me, and I liked having a little sister, I looked out for her, allowed her to do things that mom would not let her do, just little things like sneak into my room, which was in the basement and watch late night TV, or have snacks when she wasn’t supposed to and in return she used to look out for me give me heads up on things she heard mom was upset with me for or let me in her window at night when I would sneak out.
One night, and to this day I still don’t know why I started it, seeing how I loved Faith so much and looked out for her. She was in my basement bedroom and fell asleep in my bed next to me, which wasn’t that unusual. I was 16 at the time and she was 7 at the time I had been masturbating for about a year, almost no porn or anything like that, it was the 80’s no internet and porn was hard to come by. As she was sleeping I was jerking my cock ever so silently when I got the urge to just look at Faith, she looked so cute and pretty. I had never seen a naked girl for real and just wanted to see what a pussy looked like. So I lifted off the covers from her and slowly pulled down her little pink cotton panties. The entire time I was scared to death of getting caught, I knew it was wrong, but it wasn’t like I was going to hurt her, just look.
With her panties down I saw the tiny bald mound between her legs and not much else, I slowly spread her legs. There before me was the tiny slit, and I mean just a slit with a little lip protruding out. I couldn’t resist and had to touch it, I slowly opened her slit up, there wasn’t much to see, just a little pink reddish skin. I didn’t dare do any more. I just kinda knelt there and began to stroke my cock, for a 16 year old I knew I had a big cock, I had measured it a couple of times and when really hard it was 6.5 inches and 6 inches around. I knelt there pounding my cock, licking my hand for lube, watching Faith sleep. Soon I could feel my cum starting to rise, I so wanted to be inside her but I knew I couldn’t, I put my cock right up against her little slit and blew the first cum shot it flew up her tiny body and hit her right on the face, I didn’t care I blew stream after stream of cum on her body and tiny pussy, It was by far the biggest cum shot I had to date.