My girlfriend doesn't want me to meet her cousin sister and I don't know what to think of it?

[Anonymous]

For context she talks about her at least once a day and sometimes compares herself to her. She has this love-hate thing going on with her like she likes to hangout with her occasionally but also complains a lot about her to me. Couple of months ago she and her sister pulled a unknown text prank on me but I knew it was her sister and texted her next day that I knew and we had a causal talk. But when I told my girlfriend that I texted her sis, she flipped off and started belittle me that I am a nobody to text her even if she was the one who pulled the prank. Even at the present I wanted to watch the new Spiderman so badly and asked my girlfriend to go with me but she denied but she is going to watch the same movie with her sister so I asked her to go all three of us as tickets weren't easy to get but she denied that by saying it would be awkward between me and her sister and showed me discontent. I can't make any sense of it.

[average-j0e]

her sis mightve fucked a boyfriend in the past, I've been in that situation. just dont fuck the sister. ur girlfriend will be happy with an awkward rejection to her, much more than just doing nothing. just phase out with small sentences and one word replies if she texts u and dont talk unless you're face to face. thats when you shut down any subtle advances. like bro i got flashed while my girl was right next to me. shortly after it happened too. crazy shit. the sis figured out i wasn't gonna go for it tho. never told girlfriend about her flashing me, i knew it would cause problems, and that i wouldn't do that, especially to her at the time but tbh she's pulled someshit i gotta get even somehow :p probs wonr happen i can be a turnoff sometimes too much emotional baggage to sort out but i mean damn the guyus wouldn't even tell me what happened like fuck thats more than just talking shit...