Nothing I should worry about?

I've been together with this girl for 4 months now, she used to go out with someone I know, I don't know what really happened between them, but I'm sure she loved him. He left for college and they broke up, not sure if that's the reason they broke up, but he left for college. But even after he moved and they both broke up, they both still talk almost everyday... should I be concerned?... I know i am a really protective boyfriend.. but I don't understand how she would still talk to someone she used to have a relationship almost everyday.

I won't lie, I wouldn't like it.

I wouldn't like it. He's just on the back burner. It sounds like they're having an unofficial long distance relationship and you're what we like to call a placeholder.

Yes. Suspicious. But it could just be a matter of they having stayed friends after the break-up, although that good friends is a bit rare.

I talked to her about this...

I first asked if she loves him,and she said a part of her will always love him, same with all her past boyfriends. Then I told her I feel like someone you fell back to because he left. Then tells me that there's a difference between me and him. She says she loved him, but it wouldn't have last even if he didn't leave. She says she's "in love" with me and she's sure of that. And she told me she doesn't rebound. "I wait and move on, as simple as that." I don't know.. she still talks to most of her Ex boyfriends.