I wasn’t really sure where to go with this question, I know there are some very knowledgeable people around here so I’m hoping someone can help.
So… my father died when I was seven years old and my mother never remarried. My mom was always distant, usually busy with work. Me and my siblings were on our own a lot and BOY did we fight sometimes. It could get pretty vicious. Now that I’m an adult I finally realize that the loss of both my parents (father through death, mother through her being a work-a-holic and emotionally unavailable) made me really crave normal emotional intimacy that anyone should have in their immediate family. So, to meet this need, when I was somewhere around the age of 12, a sibling and I would be…uh…intimate in very inappropriate ways. We did things multiple times and my sibling is less than two years older than me so it wasn’t like an older child was preying on a younger child. But then there is a huge maturity difference between 12 and 14, or 13 and 15, or 11 and 13. However old we were. But anyways, we did these things a few times over a timespan of maybe a month or something I’m not exactly sure, it wasn’t long, but then we put a complete stop to it because hey guess what it wasn’t fulfilling that need for real intimacy among family! And we haven’t spoken about it since. I do remember these actions quite clearly, and there was no lust involved. It wasn’t pleasurable at all, I remember feeling like it was gross. But it was perfectly mutually consensual among children very close in age so it is not sexual abuse. I don’t remember who initiated it, we probably saw something on TV or something, I don’t remember.
But we were above the age of reason. I’m wondering if this was mortally sinful. I wasn’t lusting after my sibling but we were doing things that between two unmarried young adults would be mortally sinful.
So…I’m just kind of confused. What is it that makes sexual acts outside of marriage sinful? Is it the lust in your heart? Or are the acts in and of themselves sinful and it doesn’t really matter what you’re thinking/feeling during the act (outside of things like rape of course, obviously nonconsensual sexual anything isn’t sinful).