My girlfriends extremely close guyfriend

I have been dating my girlfriend for a year and a half now, and just recently have been realizing the magnitude of her relationship with her male friend. He is living in North Carolina and we are in Arizona. They have been friends longer than we have been dating, but it is coming to a point where I want to take the relationship to the next level, but the only thing is I'm not sure that this is wise due to being unsure just how close she really is to this guy. She talks to him every day, she texts him every day, even sometimes when we are hanging out, they make it a point to talk on the phone every other day. I have expressed that it bothers me she texts him when we are hanging out, and she has stopped doing it so much, but she still does every now and then. Just recently I was going to post on her facebook wall, and saw a message she had sent to him saying "Where are you I need my Michael time." I have asked her about it and she said it doesn't mean anything. She said My heart is with you. But I wonder if her heart is with me then why does she need to talk to this guy so much, because the moment I knew I was in love I stopped having frequent contact with all the girls of the opposite sex that I'm friends with, and never even talked to them every other day. I have talked to her about how the frequency in which they talk bothers me and I don't understand why she and him talk so much. She just said she can tell him anything, and they are just good friends. jokingly before we were serious and even after we got serious she had, "in an open relationship" on her facebook, she said it was a joke between the two of them. I asked her about it and she said it was a joke.

I talked to her about all of this and she just said they are just friends, that she loves me, and that I shouldn't worry about it. She isn't going to stop talking to him as much, she isn't going to do a thing about it, she basically just said deal with it in a nice way. She asked me how I am going to react when he comes to visit? I said I am going to be very uncomfortable, and I have no idea. I told her that I don't feel the need to be that close to any other girls because she was fulfilling enough for me not to have the need for so much contact with the opposite sex. Now i have friends that are girls, but I would never talk to them as much as she does him. She isn't willing to do anything about it, and it makes me wonder if when she says she loves me, does she really?
I don't know what to do, but I don't think I can go on knowing that she isn't willing to do anything about this, and knowing how I feel. I'm not jealous, but I am just bummed because i couldn't see myself talking to another girl that much because I am in love with her, but she doesn't have the same view as me. I've tried talking to her about it two times already it's always the same thing.

I NEED ADVICE