I am a Leo and I have had a longtime relationship with a male leo. Here's what I think:
He may think you are not that into him because as a Gemini, you may not be giving him the devoted attention that we Leos crave. It sounds like he keeps pitching you softballs and you won't take a swing. If he wasn't interested, he wouldn't keep texting you. We Leos can come off as confident and popular but we have our insecurities and we don't take rejection well. He is probably used to women throwing themselves at him.
I think you should invite him out. Maybe to one of your DJ gigs. If he's interested he'll show up. You can have drinks afterward. If he's not interested, he still may show up but with a date!
Oh and don't be surprised if he is going out with other women. We like to keep our options open until we find "the one". Don't take it personally. We just love attention from those we are attracted to and Leos often attract many people.