I (17M) need help with my relationship with my gf (16f) please help me.

As said in the title, I'm 17 and my girl is 16 and I genuinely don't know if I'm in the wrong and overly jealous, but I need advice.

Basically, my girlfriend has a guy best friend, who she calls her brother and he calls her his little sister cuz they known each other for years. She often speaks to him and even goes to him for advice of our relationship. I also found out from their WhatsApp statuses that they even call each other.

She is even still rlly close with her ex, and often spends time with him.

Now, don't get me wrong. She would never cheat. That's not who she is. And she hasn't even kissed anyone except for me and her ex. So ik she wouldn't do anything like that. But the thing is, it's uncomfortable for me to see that she is spending so much time around guys. And then when I dare to be around a girl at my youth who I am kind of close with, then she gets jealous.

I've told her before that I'm not a fan of the guy best friend thing, but that won't change, so I decided to just leave it. But the thing is that she knows that I'm insecure cuz of past relationships being really messed up and me being treated horribly, and I was constantly being lied to within the relationships.

Now, ik u guys are gonna be saying "she isn't your past relationships" and "she isn't those other girls, it's unfair of you to put her in the same classification as her." All valid points. However. Understand where I'm coming from. I have Tourette's syndrome, and have had it since I was like 2, it comes with ADD, OCD, ADHD, depression(not always, but often), anxiety and alot of those things that the tiktok kids are faking. And this causes me to genuinely struggle with the whole thing. And like I said to her, I don't expect her to cut him off and never talk to him again and all that stuff. Not at all. I just wish she would distance herself a bit, as I did when I got into the relationship. I cut off a few of the girls I was friends with and I have distanced me from the others. And again. It's her choice. But it still hurts.

Like I said, I've expressed my feelings towards the issue with her before, but she didn't change anything about it. She says she loves me with her whole heart and that she won't ever leave me. Which I believe(even tho all the other girls said the same.) But I still feel like it's kinda unfair towards me.

The moderator bot won't let me ask for judgement on myself. But I need it.