I met this awesome guy. The only thing is I am in a relationship already!?

Ok call me a cheater because that is what it is. I met this awsome guy about a month ago. We been going on dates and we can sit and talk for hours we have so much in common.He takes me to plays and art shows wich are my favorite.My boyfriend and I have been living together for about three years. He never wants to go anywhere all his friends are always over our house playing games and eating all my food I cooked. We argue about everything and he only helps out with our daughter when asked. We do love each other but he needs to grow up I talk to him about it but he doesnt listen. I tell him that if he doesnt get his act together I will leave him but he thinks im bluffing. Should I keep seeing this new guy and tell my boyfriend its over or should i keep things as is and work it out with my boyfriend and let my the new guy go.