My Crush Is Dating Someone Else...

I'm 14 in the 8th grade so sorry if this sounds a little childish... So I've like this guy for a while now but the problem is, he's dating someone. I didn't know they were dating when I first started liking him. It's obvious he likes me back though. He always smiles and stares at me in the hallways and he asks my friends about me when I'm not around. I think about him 25/8! His girlfriend doesn't even like him! She literally talks bad about him and likes his friend. I've thought about breaking them up but I'm not that kind of person. And it's not like I can just convince myself to stop liking him either. Please help...