what to do with a boy bestfriend

Problem/Goal: i am uncomfy with the relationship of my gf and her boy bestfriend

Context: im a guy (23) and i have a gf (22) na merong boy bespren. now okay, i also have female friends and all that and i do understand that platonic relationships exist because i also have those. but the thing is, she tells/rants/vents her problems (particularly OUR problems) to that boy bespren instead of me. and that dude also rants to her abt HIS relationship problems. she told me that the reason she cant tell me was because we've already talked about the problem and she doesn't want to deal with it again (i found out that it was kind of a new one) and it was hard to tell me about it. she also told me that she wouldn't even rant to that guy to begin with if we didnt have misunderstandings in the first place.

i was supposed to be okay with their relationship before but now, parang every interaction between them, it makes me uncomfy. although she told me that she's not gonna rant to that guy anymore, they still interact. nanglilibre parin ang guy and all that sa kanya.

What should I do? What should I feel?