What ever you do, DO NOT ask about that night or if she likes another guy. If you love her just allow her to love you do not force her, don't seem to desperiate do the same with other girls, you don't have to love them or even like them. If you are not together she has no reason to not lay on other people. If it upsets you play it cool. do not confront her. If by chance you know she likes you, don't question it. I have made that mistake with questioning my girlfriends feelings, she said she loved me, but i had to always ask about it. now she is gone and i have lost my love. so just play it cool. have FUN when you go to see the movie. always have FUn she doesn't want to be conserned with "love" right now. take her out if she enjoys it with you she will like you.
sorry i'm rambling, i hope i helped just a little. Good luck