How do i live in a negative atmosphere?

I have been through alot in my life and yet everyday i wake up and try to be positive about everything. I love life and people and animals. Everyday I clean up the house and take care of the two dogs and pretty much do everything here. I am nice to people and caring. I live with my boyfriend, his son who is 25 and his girlfriend. My boyfriend does nothing but get up and move to his chair and sits there and watches TV til midnight, The area where he sits in the living room is very sloppy with overflowing ash trays and pop cans. He is always mean and crabby when you try to talk to him. If you leave him sit there all ay he is fine if he doesnt have to do anything or talk to anyone. He can be very mean and cruel to me. His son and his girlfriend spend about 14 hours in his room. He comes home from work and goes to his room and comes out when its time to go to work again. no friends and no social life at all. He is also extremly messy and dirty in his room. Its like they all have no life and do not care about anything. They all hate christmas, hate valentines day etc and are very antisocial. They only like heavy metal music and say they hate God and to keep my God to myself. I am a nice person, soft and sensitive, I am a christian. This is such a negative atmosphere and lonely. I have never seen people like this before that have so much anger and i dont care attitudes. I am so positive and easy going. My boyfriend gets so argumentative at me. Its like they all hate life and it is so hard to feel good here everyday. I dont have ajob right now but i am looking.Its hard to sit here and say what are ya doing for valentines day and get a response like " i hate VD who ever invented it should be tortured" I feel so different then them. why are they such loners and negative and angry all the time?? What can i do? and how do i deal with this.