I listened to my grandma pleasure herself for a whole year

so for context i (17f) was (past tense) sleeping with my grandma because we didn't have any other room so we were just lumped together. And for the first few months, I would be awakened at night by the soft squelching noises and muffled moans coming from the weight that lay beside me. I would like to think this occured once a month, but that would be a lie - every couple of days I'd hear the same thing and shut my eyes and pretend like nothing was happening. I don't want to be a disgusting chud and think my own sweet grandma was touching herself - what kind of crazy person would think that. until i procured physical evidence. one day, my poor 16 year old self awoke on a groggy morning for school. the lights were turned and my grandma had slipped out of bed and gone downstairs - probably to make herself a cup of tea. I brush my teeth and enter my room again... AND HARK?! What is this small wet stain on my grandma's side?! my theory was CORRECT? (yes that was the first thought that occured to me) - following a very uncomfortable and difficult conversation with my mother, we changed the sheets that same day (after school). but the touching never stopped. i am safe now.