Friend girls

So I have a thing with a guy and have done for awhile, he’s been asking me to go on a walk with him for awhile and today I finally asked him if he would.

He’s close with a girl I’m good friends with and they have a lot of romantic history with. I’m not one to be jealous but she’s at the top of his bf list on sc, they FaceTime all the time and go on walks together alllll the time. I know they’re really close but idk it’s a bit weird, she’s been really overly friendly with me at the moment :(

When I asked him on the walk, he was like I’m meant to be going on a walk with the girl and two of her hot friends, like he’s told me before he thinks all three are so hot, and he said we could go on a walk as long as they don’t clash. I’m such good friends with all of these girls so I don’t know why he didn’t just invite me. It’s making me very worried, and I feel like a jealous, untrusting bitch, I hate it :(