Im so confused

uld I ask to define the relationship?

So about a month ago I answered a personal ad online for the first time and we really clicked and so a few days later we met for the first time and we have gotten along great and I really like him a lot. About the fifth date slept together and everything seemed to be going well we have hung out a few times since then and have spent the night a couple of time without having sex. How ever things seem different this past week we have barely talked and he hasn't asked to hang out and I did ask if he wanted to but he said that he was going to hang out with his parents. So I know it sounds stalkerish but I was feeling paranoid and went to the website where his ad that I responded to was and it turns out he reposted an ad the day after we had sex for the first time but that was 2 weeks ago and things seemed to be going fine since then except this past week. So that's the back story so I dont know if I should ask if he is even interested in being exclusive or if I should just end it before I get attached