The guy adores his cat, he shows his capabilities to assert his feelings. Most girls would love to be in your shoes! Especially when he says he loves you more than his cat too!
You look at that likes it's nothing, because you don't feel the way he does toward his cat. If you look from his side it's a huge compliment. He loves his cat, that part is obvious to you, he loves you more than his cat, this part you reject because to you "it's just a cat", but to him it's an animal he loves and cares a lot about.
You haven't explained why it bothers you by the way. It's something positive he has in his life, that makes him happy. You also say everything else is nearly perfect between you guys. You should ask yourself why it bothers you so much, especially when it's something positive in his life, it should make you feel good to see him happy, but instead it's upseting to you.
Are you jaelous of the attention he gives his cat, you want 100% of his attention to yourself? Or is it something else?