Do I have the right to be upset and hurt by what my hubby did?

My 22 yr old daughter graduated from College last Sat. My hubby of less than 3 yrs and I attended the ceremony. I noticed about 20 minutes before the ceremony my hubby kept moving around and then started complaining about his back hurting. He has back trouble but so do most people in there middle 40's. I myself have sciatica and tailbone problems. We were sitting in a gym with wooden bleachers and on the front row. He kept saying the lady behind him had her knees in his back. So he left. About 10 minutes before the end of the ceremony he comes back inside. He said he was sorry but just couldn't take her knees in his back. Thank God my daughter doesn't know he left, she thinks he was there the entire time. Next week his kids graduate from high school. I can almost guarantee he won't have any problems with sitting through their graduation in a smaller gym with someone's knees in his back. I am hurt and upset with him. But he doens't understand why...are you kidding me. I am sick of everything being about him and his kids. Am I right to be upset and hurt?