Mooby the cat

Now that Sammy is gone, my boyfriend has asked me to think of his cat as mine too. The only problem with that is the fact that his cat isn't very friendly...except to my boyfriend. His cat Mooby is the type of cat that when you reach down to pet him he will either swat at you or move away from you. I've tried to win his affection by giving him treats, but after several years of this, its not working. Mooby only loves one person, and its not me.  At one time, he even peed on the chair that I used to sit in when I was over there.  I'm wondering if this behavior will ever change, especially since my boyfriend and I are talking about moving in together.  Even his mother agrees that his cat is not very nice!  My biggest concern is my furniture.  I'm afraid that he will destroy it the way he has destroyed all of my boyfriend's furniture.  The fact that he does nothing to discipline this cat has become an issue.  This cat basically runs around and does whatever he pleases!  By the way, the chair he's sitting on (in the photo above) is where I sit when I come over.  He gets really pissy if I push him off.