Is it normal when you dump a guy that he acts like this...?

Hey, I broke up with my boyfriend of 3 months last week because my feelings had changed and I was trying to be honest about how I felt. We are both in high school. Anyway, we had been at a mutual friends house for the evening when I told him I didn't want to go out anymore but of course still be friends...yeah yeah I know..."friends". Well, I have left comments a couple of different times on his myspace and he doesn't respond at all. Geez, it's not like we were married for 10 yrs. or anything!! What's the deal? Why can't he just let it go or at least pretend for appearance sake to let it go. I mean we have 4 yrs. of high school left and have many mutual friends. Is this normal for a 15 yr. old guy? Thanks!