Another psych check

Another poll to check my behaviors while I analyze my mental issues. Sometimes when I masturbate I think of my father. When I was young my father used to pinch my behind or my nipples. It was never in a sexual or casual manner, always, every time, he did it in a joking manner, like he thought he was being funny. Once when I was 12 he asked if I would come in his room and be his model for some pictures but we never went to take any photos. It wasn’t until I was 16 that I realized my dad probably wasn’t joking. He and my mother had divorced after 20 years of marriage. My mother said he was sexually abusive and didn’t truly understand to leave until she started to fear for her daughters, as they were married when she was only 16 after a childhood full of sexual abuse and foster care. At 16 I was sent to live with my father because my mother was having a hard time dealing with my mental issues. After I got to his house and unpacked my father told me that if I wanted to I was allowed to walk around the house topless, or even naked if I wanted. I didn’t know what to say so I just said “okay” and left it at that. I never took him up on his “offer.” Over the next month he would try to take me shopping for thong underwear and continue his “jokes”. I got in touch with an ex and told him about what was happening. He purchased me a greyhound bus ticket to his house and I ran away when my father was at work. My father has since gotten remarried and we have a very strained relationship. I never told him that I felt sexually violated by him and as an adult (I’m 26) I sometimes think about what my father would have done to me had I wanted to go along with his fantasies. Is thinking about your father during sexual activities a common fetish, a part of a mental disorder, or an after effect of feeling sexually violated by my father during my childhood? Please don’t be rude about this, I am honestly trying to analyze and process my life and my mental state in attempt to improve, heal, and protect myself and the people I care for from my mental disorders.