My guy best friends girlfriend might be jealous

My guy best friend and I are very close and have a sibling bond. We are both in very happy and loving relationships. Recently his girlfriend who I am friends with seems to be a bit jealous. My guy friend had invited me to a trip with him and his family a year ago before he and his girlfriend started dating and we have talked about it ever since. Out of the blue he texted me saying I couldn’t come on the trip anymore and then proceeded to say well I don’t know it depends on what his girlfriend thinks. I asked if everything was ok and if they had another argument as they have recently had one about him and I being close and he said no he just wanted to be a good boyfriend. It seems like he is lying to me and then he said that maybe if my boyfriend came with us it wouldn’t be a problem. I am a bit concerned about the girlfriend as she has problems with me but will not confront me and rarely tells my best friend about it. She is not allowed to see him and they have difficulty communicating outside of school but should my friendship have to suffer because of this? like I mentioned the girl is not allowed to hang out with him outside of school so it makes things difficult for their relationship. She knows that we do not have any type of feelings for each other and that I love my boyfriend dearly. I am not sure what to do and have offered to speak to her as we are friends and my best friend asked me not too. I didn’t think our friendship would be a problem but this has come out of the blue and is starting to become concerning.

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