How can I find out if he still has feelings for me ?

He is friends with A LOT of girls so I don't know when he is flirting or not. He is also cool with all of his ex girlfriends. We used to have a "thing" until I screwed up and got a boyfriend, which ended up being an unsuccessful relationship. Today I was walking with my friends and his friends were in front of us and they all turned their heads back at us for a few seconds, I don't know why though :/. I really like him but I don't know if he even likes me anymore. What can I do?