Am I Overreacting? Hidden convos with new male friends?

Am i overreacting?

Me and my partner of 6 years/ mother of 3 my kids have had issues in the past but we have always worked through them. Last month things got heated and i called her a skank which was big bad as i dont even know why i said it. It was out of anger In the entirety of the relationship iv had no doubts she has always made me feel like im her number 1 and only. A week after the argument we rehashed some of it but calmly and i addressed the fact that shes suddenly less close, distant and alot colder than she used to be, on top of that shes suddenly followed many bikers most are for fun she says, but has a couple of them on snap and has those vanishing messages set up, so i addressed it and she was going to end the relationship because i mentioned it all she saying she feels she cant breath and i dont mean to suffocate her in any way i truly love her. She decided i can stay but ever since, im still concerned about her having these biker guys with disappearing messages, now its been a month and im trying to kick away any doubt she says they are just friends which i want to believe but says they prefer to have these disappearing messages setup and its just how they do things. For context i dont have her on snap, she says im with her everyday so i dont need to.

Id love to hear various opinions as im at the point where i feel i cant mention them through fear of saying the wrong thing when im genuinely concerned and love her and want this to work. Am i overreacting? We are both in our 30s. Id love this to just be a harmless thing. I tell myself she wouldnt lie to me, we have started a family together, but are quite distant and things seem very distant. I want to show her i can love but am i actually developing a random case of paranoia? If so to the doctors i go. Because the way my mind is constantly overthinking is really making me feel like im starting to go crazy living in my head to the point im now having nightmares about her leaving me for another. Dod i randomly create this fear? Are my concerns genuine? I dont know im just trying to understand. I love her and dont want my mental health to affect us in any way. Someone please tell me im overreacting as this is the thefuture of our relationship and our family at stake, she says she loves me and i love her. For reference i have been a bit of a dick at times and hard to deal with in past as im BPD.

Any help much appreciated