Boyfriend went behind my back...

Yesterday my bf took me to Disneyland for my 21st. I was so excited about this day & he wanted to make it the best day. Right when we got into the parking lot there, my mom texted me saying have fun. I exited to my other messages, & saw that I sent a text to one of my guy bffs at 3am. I was so confused, but figured out it was my bf who did it. My guy bff texted me a long paragraph at 3am telling me happy bday, he can't wait to celebrate, he loves me, I mean a lot to him & he wishes all the best.My bf texted him "well she means a lot to me too bro. Don't get it twisted."

I understand why my bf saw it the way he did. While I used to dorm at college, I would always hang out with my guy friend, other friends, & my roommates together. I would very rarely only hang out with him (maybe one out of 3 years ?). We have a very tight group of friends, so we'd literally all do everything together. He broke up with his long time gf last semester, & it broke him. He came to me first (through text). He was really down for a while & we all tried to help him. He would make some weird comments from time to time, & my bf knew of it.

Back to Disneyland, I felt betrayed. I asked him why, & my bf told me I'm his & he doesn't want anyone to take what's his. I told him he shouldn't have done that, at least talk to me first especially if I'm asleep. I started crying because I felt like he overstepped his bounds, but didn't at the same time. And on my bday. He told me he was crying on the inside because he thought he did the right thing. Apparently his gf before me had guy bfs that she talked to all the time & left him for them. I've been with him for 3 years & have never seen him act like this. We talked about it & pretty much got over it (I was still a little pissed throughout the whole day). All day long he kissed me & was saying I love you & was really going above & beyond for me.

This morning was my actual bday. He left at 6 am for school. I continued to sleep for a little while longer & then go home. He ended up coming back after school to surprise me & be with me a little longer (≉). He's been sending me hearts all day (he normally doesn't) & called me tonight asking if I miss him. I said yes & he said he misses me too (he rarely says that without me initiating it). I don't know what to do. He's making me feel SO special, but at the same time I just can't stop thinking of what he did.

Little UPDATE: My bf has never been possessive or seemed insecure in our relationship at ALL! Usually I'm the one always overthinking & "making sure" were good. That's why I'm surprised he's telling me he misses me multiple times today & that he loves me.