My gf left me after she found me touching a poster of david helhoff?

My gf found me masturbating and touching a poster of david helhoff, but i had no idea she was behind me. sometimes when we had i used to imagine she was david helhoff but i never said anything about it. I don't understand why she weirded out. It's not like I actually cheated on her. she took things too seriously and let david come between us but i'm not going to apologize so she can get lost good riddance.