Is he really being a or am I crazy?

Okay, so my recent ex-boyfriend just broke up with me on Saturday (over TEXT MESSAGE) and then yesterday (Wednesday) he took my BEST FRIEND out for a big birthday celebration thing that included lanterns, balloons filling his car, a picnic, dinner and a movie. Not including the "actual" gift that he got her which was a photo journal that had quotes from different group outings and such that I helped him make before we broke up. When we were dating he NEVER did anything like this for me. The most romantic thing that we ever did was watch a movie in his basement. And he's not even dating her! He would even stay up all night talking to her while we were dating and then come to school the next day and complain to ME about how tired he was. He claims to mutual friends that he's only doing this to make her feel special because she has really low self-esteem, but my constantly telling her that she wasn't "invisible" never seemed to work, because, in my opinion, it's just her looking for attention. Attention that he's giving her freely even though she's 17 and should be able to act mature enough to just talk to me instead of ignoring me whenever we're around each other. One of that hardest parts about all this is that i WANT to be the bigger person and i WANT to be friends with both of them again like we were before all of this but I don't know how to do that because I know that THEY are in the wrong. Advice/opinions?