Boyfriend and Gay Friend

I have a new friend who is gay. I walked by him today and touched his shoulder, and my boyfriend got mad about it. He said it doesn’t matter if he’s gay or not because he’s a guy. I told him if he had done that to a lesbian I wouldn’t have cared. It’s the same thing. He says I’m lying and would actually get mad. It’s hurting my feelings and it’s extremely frustrating. How does he not understand that my friend is GAY? Am I wrong to think this? I need advice.