My girlfriend opened up about her fantasy

Last month in a weak moment while I was fingering her and kissing her, she looks so creamy. she confessed about her fantasy. She wanted a guy to join us. Basically a threesome. She has been watching some movies with such scenes recently maybe that's the reason. After that she never talked about that. Later few days back, she told me that she watched a movie and fingered herself and enjoyed it So good. She asked me if I want to see that movie too. When we met, she played the movie and there were scenes where a girl repeatedly enjoying threesomes. She sucked me soo freaking good while I was watching those scenes. I get it! She's trying to convince me. It turns me on soo much but....... I am so jealous about that. I swear, this really happened. I have been thinking about for few days to post it here. What should I do?

we can talk about her but I can't share her images as I am not ready yet.