My training partner problem

So I made friends with this guy at my local gym. He's this really buff black guy in his late twenties and he's really a popular guy. We are at the gym usually at the same time so we eventually, after talking began training together 2-3 days a week which is awesome cause he really pushes me. A few weeks ago he finally told me he was homosexual, which is fine by me. He's an awesome guy and I have no problem with gay people. But lately he's been pushing me to go on a "date" with him even though I keep telling him I'm straight. I think he thinks I'm gay just because after are work outs I kiss him in the locker room. What should I do?