Unable to tell wife my secret

In an attempt to spice up our sex life, my wife brought some sexy underwear. She doesn’t understand why, rather than turn me on, it seemed to put me off, and has taken it as a personal slight. What she doesn’t know is that it simply brings back bad memories for me. For a short period in my early teens, I stayed with foster parents, during which time I suffered sexual abuse. Every so often, one of their friends would come around and I’d be forced to have sex with him. This guy was a mixed up sicko – even though he was using me, he had a thing for sexy women’s underwear. So much so that I had to dress that way when he was paying a visit. Seeing my wife dressed like that just brings back memories of me as a teenage boy, seeing myself in the mirror in bra, panties, suspender belt and stockings, climbing astride this monster and desperately trying mot to lose it as I guided him into me (as I’d be punished if I made a fuss). How can I possibly put this picture in my wife’s head? But if I don’t, how can I explain to her my apparent lack of interest?