There's been some evidence that suggests that sexual sadism and masochism are in fact full fledged sexual orientations. The study was far from conclusive, but it's food for thought. The above comments about either enjoying it or not are fairly accurate. Most of the anecdotal evidence (mind you that's hardly reliable, but lacking sufficient studies we'll roll with it) from individuals I've spoken to suggests that individuals become aware of the preference during puberty. That said, human beings are easy enough to condition. If you are genuinely interested in forcing yourself to enjoy it, then I would suggest watching bdsm pornography and masturbating to it. Crude, I know, but in time that should condition you to find the visual stimuli arousing. This will help to more fully enjoy the activities you and your partner engage in. Just please be mindful that there is a marked distinction between the depictions in pornography and a real, healthy, bdsm dynamic. Never engage in any form of play with out first doing sufficient research and taking any requisite training courses.