Is it wrong for me (22F) to be jealous of my boyfriend (24M) of two years and my best friend (21F) and what are some ways to get over being jealous?

So recently my boyfriend and my best friend have gotten really close. One way to put it is that she’s like a “little sister” to him. I know there is nothing going on between them but they just have so many things in common with each other that when we all hang out it has started to feel like I’m the third wheel. Like today they were proposing to go watch a movie together on a day that I had set out to take my boyfriend out for his birthday (I had discussed this with both of them). And I recently found out that they are also going out for dinner together during a time when I’m busy even though we are all free just two days later. (I know we all don’t have to hang out, I just find it strange that this is a place I brought up wanting to go and now they have plans together). Lastly when we were watching a movie recently at home, my friend sat between my boyfriend and I and he had his hand up on the sofa behind her head (not around her I guess but in all our years of dating he has never done this once with anyone else).

Anyways, I just wanted to ask if I’m being crazy and if so are there any ways for me to control my jealousy lol? I really don’t want to be the jealous type (and I havent ever been till now).

TLDR: My boyfriend of two years and best friend have recently gotten close, started hanging out without me, and idk if I’m just becoming jealous, or if I should actually be worried?