So, there is this new guy, and i think we are starting a new relationship. But, I cant help but notice that he's already mentioned his ex girlfriend 3 times sinces we've been together. He doesnt talk about her he's just mentioned her, on 2 things that we have in common. Does this mean he's not over her? or he's just making conversation?

He might not be over her, or he might just not realize how tacky it is to compare a new partner to an ex - especially if it's early in the relationship.

Some important questions could be:

How long ago did they break up?
Who broke up the relationship?
Are they still friends?
Does this guy have any other strange lack of social skills?

If he's the one who is bringing her up, and you feel that this relationship is becoming serious, it's reasonable to ask some questions. Though, you might want to demonstrate tact to him by not asking them as pointedly as they're worded above!

It really depends on how the relationship was. Just like the other poster said you really have to look at the facts of his past relationship in order to figure out the answer to this question.

I visited him across the country, and at first he was all excited, then he started giving me the cold shoulder. Like he's sorry cause he has no time, cause he has to work 12 hour days, which is true. So, i found out from his friends that his ex is still coming around and basically playing games with him. Since, i visited him, he realized how me being there could look to his ex...Unfortunate!