Help I have a crush on my best friend :(

Honestly this is kinda embarrassing to type out, but I genuinely don't know what to do. I (18m) have a crush on one of my best friends (17m). We were friends for a couple of years, but got really close last year bc we actually found out we had the same toxic ex lol. I helped him through her guilt tripping, of her trying to get with him again by threatening to end her own life MULTIPLE TIMES. And after that, we sorta just got really close. We hangout all the time, hold hands, and flirt with each other as a joke, but it's not a joke to me. I just can't help but like him. He's a great person, just really nice and talented, and I can't stop thinking about him. I would ask him out but I don't want to ruin our friendship. I have been rejected multiple times, and even bullied for liking people. Hell, I've even been asked out as a joke multiple times! I'm scared that he just sees me as a friend, and would feel disgusted if he finds out I see him more than just that.