How can I stop hating my boyfriend s cat?

So I ve always wanted my own cat and thought that my 23 yr old boyfriend of 3 years and I could get one together, but he can t afford to move out of his parents house and they refuse to let him get another cat even though we would take care of it. Currently, I stay over most of the week btw. We pretty much live together. This is where the other cat comes in, and he s the family cat. They ve had him for several years. Because he s so violent against other animals, my boyfriend and his parents won t get another cat. To make matters worse, the cat they have now hates to be touched. I ve never seen a cat so unaffectionate. He comes up to my boyfriends room while we re together and just sits on the stairs licking his ***. When we approach him, he runs away. I hate this cat and desperately want one of my own. How can I stop hating him?