Boyfriend super jealous ?

I'm going to try to make this short, but I've been with my bf for over 3 years now. Two days ago he took me to Disneyland for my bday. Right when we parked I noticed I texted one of my guy bffs at 3am...I was super confused because I didn't. I figured out that it was my bf. My guy friend texted me a long paragraph saying happy bday, & while I was asleep my bf texted him telling him that I mean a lot to him too & to not get it twisted. I instantly got upset because I feel as if he went behind my back, something hes never done before.

I've known my guy bff for 3 years now well at college. We would always hang out almost every day (with our whole group) while I was dorming there. He broke up with his gf of many years last semester, & he came to me first. Some of the comments he's said about me have been weird & ive mentioned them to my bf, but that's it.

After crying in the middle of Disneylands parking lot, he told me his gf before me left him for her "guy bffs" & he doesn't want that to happen. I told him it would never. He apologized but just said he was trying to protect what's his. The WHOLE day there he was telling me he loves me, kissing me, & etc. (which was excessive for him). The next day, my actual bday, he was doing the same. I went back home & he was texting me hearts & saying he loves me. He called me later that night & said he misses me which he doesn't do unless I say it first. & he said it MULTIPLE times! Today, he's still doing the same. Usually I'm the one who always overthinks & does that, but now it's him. I've never seen him act this way & it's weird. Idk what to do...