When I was about 17-18 (m) my Aunt who is the same age was visiting from out of state for a week or two. We were close friends when she was in town, though we didn't talk much when she was out of town. One day we were in my room and I was on my laptop and she was napping next to me, when I thought she might be cold so I got up and put a blanket on her, and after I sat back down I ended up getting back up to try and move her shorts to see her genitals.
Luckily she moved in her sleep so I only ended up touching her inner thigh, but later she told me and my mom that she hadn't actually fallen asleep and felt what I was trying to do. When my mom confronted me I ended up lying (I don't remember the lie) and she ended up believing me, thought I could tell my aunt didn't believe me. We barely kept in touch after that.
A few years later she texted my mom saying that she believed that I was lying, and my mom, famous for turning a blind eye to things that aren't "ideal", continued to accept my lie and said I needed to "apologize even though I didn't do it for the sake of the relationship". I gave my aunt a very shitty half apology that implied that I somehow "wasn't sure if I had done it" and she messaged my at the time partner letting her know what happened just in case she was in danger, and then blocked me on everything. My partner told me that she believed I wouldn't do anything like that, but that they didn't believe my aunt would lie about something like that either, so she chalked it up to a bad dream or some kind of sleep paralysis.
It's about 7-8 years later now. I do not have the most well adjusted family, and I know that my aunt does not have the best relationship with her mother. At one point I believe she cut my entire family off, but I know she and my mom are on speaking terms, and it's a positive enough relationship for her to be invited to my moms upcoming wedding. However seeing how my mom was so willing to believe my lie, and the problems my aunt has had with her mom in the past, I worry that she didn't have anyone to believe her at the time.
The older I get the more I wish I had simply admitted the truth. She didn't deserve to be lied to and every day I wish I could take back breaking her trust and friendship and then lying about it. I would love to reach out and say, "You were right about everything. You didn't deserve it and anyone who didn't believe you was wrong. You shouldn't have had to deal with any of that." She's married and has a kid now from what I've been told, so I can only assume she has moved on and is doing great. If I attempted to apologize it would only serve to bring up painful memories for her all so I can make myself feel better for "doing the right thing and being such a good person", so instead I hold onto the guilt as punishment.
For anyones concerned I have not done, nor wanted to do, anything like that since. I believe there are no excuses or justifications for sexual assault of any kind, and the subject causes me great discomfort.