He could be confused, but, and I am trying to help, is it possible that you want to believe he is confused, instead of maybe interested in you in a non-girlfriend way?
My advice to you is never, ever, be anyone's backup plan, unless that's all you want to be to the person. You deserve more! You deserve to be the one and only. If he doesn't want to give you that respect then please find someone who will. When you see the difference in how you feel you will be amazed.
Jealousy is not a positive thing to have in your life, and it feels awful. Try to avoid it, if you can. When he goes to the dance, try not to bosess over it. Do something extra nice for yourself. Go out for the night with friends and get some dinner, or go see a movie. Treat yourself well.
Best wishes!
