I want to echo fozzy bear's comments on the physiology aspect. The prostate is sometimes referred to as the male "G" spot.
Most of my sexual abuse was in the form of anal rape, which led me to complex feelings of ambivalence about my gender focus and the pleasure I sometimes derived from the experience. As an adult, I went on a literature search to study sexual techniques and beliefs in other cultures - and while we associate anal activity with gay activity in our popular culture, it is not the case in some eastern traditions, where penetration, shifting roles and prostate stimulation are regarded as part of the full range of sexual exchange between a man and a woman.
Studying it objectively and removing the stigma/trigger are two different things, of course.. but the information helped me understand my body more, and allowed me to disentangle some of my identity issues.