My boyfriend's best friend is a girl?

This story has a lot to it so bare with me. I recently met this guy and we eventually hooked up. Everything was going great in our relationship until one day, I look on his instagram and saw pictures of another girl. I calmly asked who she was and he said his best friend. So I was like ok, cool. My best friend is a guy so there's no problem. Oneday my boyfriend and I got on oovoo and I asked him to take a picture with me but everytime I do, he hides his face and says no. So I thought ok, maybe he's insecure or something. Well the next day he put pictures on Instagram of them being on oovoo and I asked him why he could do that with her but not with me? He gave some stupid excuse about him not being used to me or whatever. As time went by, I noticed that him and his "best friend" talked alot more than me and him do(well at least it seems like it). It felt like she was trying to take my spot. They talked, took pictures, had nicknames, etc. but me and him didn't do too much of that. I always tried to but he never cooperated. I would ask her questions about her like "what school does she go to" "What grade is she in" but he answered my question with a question which was "why". He never gave me a truthful answer so it seems like he's trying to hide something. Oneday while I was out of town, he put a post on instagram and if he got 10+ likes, he would have to tell the first initial of his crush's name, his relationship status, and some more things. For his crush's first initial, he put "K"..... MY NAME DOESN"T START WITH A K! But guess what?....His "bestfriends name starts with it. And for relationship status, he put "Its Alright". As far as I thought, we were in a very happy relationship. We never argued and he never complained so I was very confused as to what made it alright. So I asked him about it, and once again he had some sob story.. Well Sunday, we broke up :(. He said he wanted to get his life on track, be closer to God, school, and focus more on his career but he had to let go of some people that were close to him. When he said that I thought "oh so he's gonna let go of his best friend too right?" So I was like ok, if I'm in the way of you doing what's right then break up with me. But NOOOOOO they still talk the same f****ng amount that they talked at first. Nothing has changed. But we went back and forth for like 2 hours because he said he didn't want to hurt my feelings by breaking up with me and I kept telling him its fine. As long as he's happy, I'm happy. So he finally did it and he said we could get back together after everything got back on track and I was like ok, we'll see. So I decided that this was a good time to ask about his best friend again. He told me that he's allways talking to her and giving her more attention because when they talk, They're talking about me and she's giving him relationship advice and that made me mad because he's bringing other people in our relationship. She knows nothing about me and I know nothing about her. I feel that if there's a problem in our relationship, me and him should be able to handle it without help from other people. So he basically told me that she was the one that gave him the idea to break up with me.... The b***h was trying to take my spot from the beginning of the d**n relationship and he listened to that s**t! We still talk I guess but everytime we talk, it's a brief conversation becuase he's always upset but he can never tell me what's wrong. Anyway my question is:

Do yall think they're secretly talking?
Do you think she's trying to take my spot?
What should I do?
If he asks me to go back with him, what should I say?
And any extra advice will help out sooo much. I promise I will read EVERYTHING! Thanks so much you guys!..