So complicated!

Theres this guy I like, he has a girlfriend, but he likes me back. Hes really into me and likes me better than his girlfriend. He doesnt really like his girlfriend being his girlfriend but he still likes her as a person and doesnt want to break her heart. He really wants to try a relationship with me and id love to as well, but hes still in a relationship he doesnt know how to get out of. I feel really bad and I dont know what to do and neither does he. Please help. Since all of this is happening i started doubting he actually likes me and he said hed do anything to prove he does like me, and i kinda wanna see how serious he is about this. Anyone have any ideas on how he can prove he does have feeling so me?