Still struggling with how he could just walk away and act like I never existed.

One of the big things that I do not understand is how a person can just walk away and bam, it's over. I am deleted from his life as if I never existed. I did so many things for him over the past 8 years and to just dismiss me like this is just not right? I don't know the normal process of a break-up because I believe I have always been in dysfunctional relationships. I could not do NO CONTACT if it weren't for him doing it to me. I don't get it...shouldn't there be at least some feeling there. I know that he is with someone new, but really no goodbye, no good luck, no thanks for everything, no sorry it didn't work out...nothing. Is this how it goes?