Confused on how to tell a guy something?

Okay well, this guy asked me out last night I said yes. He then later that night added me on myspace, so I looked at his profile and saw that what he called his ex girlfriend was saying "I love you, can't wait to go out on monday" or whatever,,, and I asked about her last night because I knew that they were going out but it being summer... anything can happen and you not realize it.


My question is, I really don't want to be caught in a situation where he is still going out with her, I never want to be nor to I ever intend to be "the other girl". So how should I tell him this?



(Sorry, if I worded it weird)