Hurting all over again!

Time and time again on this site we are told NC - have I listened no! 2 years on and ive let him in again - he love bombed me, dumped the women he left me for, and after 2 months of being with him, and a week ago him telling me he loved me and idealising me he has now dumped me. Got very cross when I questioned him about a couple of things I wasn't happy with - ie where did he go the previous night, nothing major, but I knew my instinct was right and he was messing around with another woman. There was a literally an overnight change in his personality - really from Jekyll to Hyde. The other night we were sat in a restaurant and he was holding my hands, I asked him if everything was ok between us as I had my suspicions the same d/d was going to happen as before, he looked me in the eyes and said yes. He absolutely begged me to go back with him, made all the right noises, said he was out of his comfort zone but would literally do anything to get me back. Nothing in our relationship in a week changed - I believe he has had someone on the back burner, and always wanted me there too, in case he was left with nothing after dumping the previous OW. I am lost for words and totally drained. I so wanted to believe he loved me and thought he must do to come back - I should know by now that will never be the case. I loved him with all I have and I hate him with all I have now. I am so upset, how can an individual do that to someone they are supposed to love. I was so angry I told him to google NPD - as I am utterly convinced there is really something wrong with him to keep doing this to people. He dumped the OW in the exact same way he did me this time and the last. What gives them the right to keep hurting people like this.