I (23m) in a relationship with (22f) getting irritated by this sibling duo!!

So I [22m] and my gf [22f] has been in an relationship for the past and we got very close very soon, since we have been talking to and fro from for already about an year before dating.

3 months into the relationship i got to know that her brother had kind of kissed her inappropriately while she was sleeping 5 years ago on her neck/shoulder.

Since that incident he has been a changed changed man but it left some residuals for me, now she is hella close to him, sleep together, discussing things like literally for hours and he has a habbit of laying his head on her lap and it is a very frequent habit let’s say 6 days a week and she has also made him slept the whole night on her lap, while she was just sleeping sitting so that his sleep doesn’t get affected(happened twice)

Coming on we have been intimate very less and and she wants to wait till marriage for everything other than kissing, we engaged in some cuddling and once we had our pvt parts rubbed and she hit an orgasm, she was so much in distress that she had to her brother(24m). Now he has commented on it that she has broken his trust about non negotiating on intimacy in a relationship.

For everything minute detail she talks to him about for hours, hella emotionally closee and he also gave slow slaps on her belly to help her sleep, she is okay with it, i was not.

Have once was sitting with interlocked fingers, i objected kii that was really some blurry boundaries nd all she said it was not wrong and there are many brother and sisters who are that closee, she is receptive to some of the stuff but majorly she doesn’t want to be questioned on her life conduction as she has always maintained boundaries.

We have had several fights on these and now she wants to break uppp!!!

Is it mee or just they have too close of a bond together??? I’m a bit overprotective tooo…

What are you’all adviceee