I was sexually abused by my father. And, as a child, one night, I also pretended to be asleep and saw him naked (he came to kiss me; most probably after having sex with my mother). I have the same feeling like you (of dirtiness, at the hands of my father) though I don't think it's a real memory (like him giving me or*l). Only the CSA is true (f*ndling at the age of 3). Though, as others said, it's probably best to address it with a psychotherapist that specializes in trauma (specifically, childhood relational trauma, if possible).