When do you ask someone if they are interested in you?

So I met this guy on okcupid in july and we went on about 4 dates within two weeks of meeting. On the fifth date i went over and we hung out for a couple hours then ended up having sex which was really nice. Since then we usually see each other once or twice a week but always have sex. Im starting to feel like that may be all he wants from me. Its now september so little over 7 weeks of knowing each other which i know isn't much.but is there a normal way to bring up "are you interested in me besides sex?" question?he's only the second guy i have been intimate with and im 24. He's brought up that he isn't seeing anyone else nor is looking to hook up with anyone but seems distant in an odd way. I just dont want to be someones fwb its not me. So if anyone has any suggestions id greatly appreciate it.