Boyfriend HATES my parents, HELP

My boyfriend (5years) has NPD and thinks it's his duty to spread justice. He gets angry and upset over the slightest things, things that a regular person will forgive and forget easily.

My parents sure have their flaws (much like everyone else), but they are not truly horrible in any way. They have provided almost everything I have ever wanted and will even go as far as BUYING me a house after I graduate from college. So, I love them and they love me, even though we have disagreements (again much like everyone else). They have also given him a job (it's not the best job, but it's enough), and have done so so much for us. So naturally, you would asume he should at the very least be grateful! But HELL NO.

He gets upset very easily over the smallest little things and complains almost daily. He hopes that they die, and that he will dance on their grave. That he will not allow our children to spend too much quality time with them. I feel sick to my stomach! I can't take this much longer.

The thing is I also (slightly) dislike his parents, which he thinks are THE BEST. They are nice people, but very anti-social and unwelcoming and although we don't really share the same values and way of life, I have absolutely nothing against them. I wish they were warmer and closer, but nothing more! I have a lot of respect for them, and would never insult them in any way.

I know all of you will say to GET THE FUCK OUT, and I probably will soon, but it's been 5 years and it's not easy on me. I feel like an idiot for allowing this to happen, of course my parents have flaws, but everyone has them. It's his ungratefullnes and rudeness that will be the end of us.

Any positive advice and encouragement?