I understand exactly what you mean. At first, it was so hard to reconcile Snape with anyone except my OTP. I am such a singular person. I still don't feel comfortable reading him paired with certain characters, but I am expanding both my reading and writing repertoire with other pairings. Strangely enough, I tend to enjoy him more Dominantly with Hermione (although I adore sub!Snape with her), and find him more enjoyable being the passive partner in other couplings. My mind works so funny that way.