I wish I'd known about NPD as I hadn't a clue. When the words 'personality disorder' were mentioned to me by the mental health social worker we worked with, I shrugged it off as I didn't really understand what it was all about.
Vivian - your post was so familiar to me. I'd have exchanges like this on a daily basis. I remember that my ex had finally - finally! - moved out of his parents' house at the age of 34. I mean, poor dear, he was only on about £55,000 a year so it was difficult for him to afford to rent somewhere...
Anyway, I trogged around the shops one day to find him some housewarming presents, wrapped them up and prepared to give them to him when he was next at mine.
Unfortunately, when he was at mine, we had a row, but I thought that it would clear the air if I gave him his presents. I brought the bag in and put it next to him and said, here are some presents for you that I thought you might like for your new place.
He leaned over, looked in the bag without even touching it and said, "I don't want it". I said, "you don't even know what it is!" He said, "yes, I do, and I don't want it. I don't want the crap that you buy me."
How I didn't end up clunking him around the head with the bag of (very heavy) presents I don't know. I asked if he would speak to his mum that way and he said, "probably".
He gave me a sob story a few hours later of not being able to accept presents gracefully. And I gave him the benefit of the doubt. The tantrums and punching of walls were very childish too and there were days when I said that he could have had an argument with a lamppost, he was just so desperate to blow up at someone.
Oh happy days.....how glad I am that I saw the light in the end.