My girlfriend is with a guy that just asked her out the other day. whole lot more in description?

alright well my girl friend (megan) is watching a movie with her 2 friends ( mark, angie ). mark and angie date and everything have a kid and all that. well theres another kid there (johnathan). there not at a movie theatre there at angies house. well 'watching a movie' is the first time me and megan had our first night intimate with eachother i guess is what you would say. well now johnathan asked her out not to long ago. my gf is a big flirt and if mark and angie kiss and stuff im scared shes gonna feel like she wants to kiss someone and right there is johnathan. girls i know you been in this situation guys i know you had a girl that did the same **** so come on what happened? should i be nervous?