I spent the whole day crying though and thinking it could still work and that it was unfair of me to spring this on him with no prior warning and not giving him a chance to fix it. I ended up leaving work early because I just couldn't stop crying. I was a mess. He had said when I told him it wasn't working that he believed he could change and I latched onto that, determined to talk with him last night about staying together and working things out.

First, you approached this with respect, and an honest attempt to provide him a chance to respond and work together to fix this relationship because you cared about it. His response was defensive, argumentative, and more directed at taking shots at you, like a 14 year old.

But just suddenly I got the urge to cry again and now I'm feeling guilty and awful again and missing him, remembering the good times and all the stuff we've been through in the last 6 years. Is this normal? How long does this last? I feel like it's going to drive me crazy. One moment I'm completely over him and feeling fine, the next I'm a crying mess, missing him and just wanting to run into his arms.

Since he is immature, selfish, lazy, and petty, Im guessing what you really miss is the idea of the relationship, and the SO that cares about you. To me, it sounds like he thinks about you like you are a set of luggage, there to meet his needs. I also think you may have projected your values and morals onto him instead of waiting, watching and evaluating his personality for hints of it. Its normal you are sad, you valued the relationship and cared for him only to find out he didnt return the feeling and was too selfish and petty to even bother when given the chance. This isnt a case of you not be worthy, unattractive, or a good SO. This is him being a black pit of lazy and selfishness. So, cry, or do whatever you need to do to purge this feeling. Then think about doing stuff for yourself, to make you happy. Focus on it. Dont focus on him, not even mentally. Then you can move on, and start to think about what qualities you want in a SO, how to really tell what kind of person they are, take things slow, and wait and see if their actions match their words.