My boyfriend's best friends are super close with his ex

Okay. I know this will sound confusing at first. My boyfriend has been best friends with Andy since 3rd grade. They grew up together. Andy got married to Hannah almost a year ago. My boyfriend dated Hannah's best friend for 5 years. They broke up (yay). He and I got together 4 years later. He is STILL best friends with Andy and Hannah. Hannah is STILL best friends with the ex. I'm just stuck in the middle. I hate hanging out with them because she is always mentioned. I mean ALWAYS. I know I'll never be close to what the ex is to Hannah and Andy, but my boyfriend makes plans with them for us. I've tried to like them but I really don't know how to. I feel so threatened by them. I also should mention the ex is STILL in love with my boyfriend and she is always with Andy and Hannah. My boyfriend says he's never around her when he goes to their place, but I just know deep down that eventually they'll cross paths again. I love my boyfriend. He got me a promise ring for our 1 year anniversary. We're going to get married when we're out of college (two more years hopefully 😜) It's been an issue for a while, but I don't know how to get over it. Maybe I am being a little crazy, but I just know things would be so much better with his friends if he were with the ex instead of me because they're already so close. Help. 😭😭