How do I get rid of unwanted houseguests?

So I moved in with my boyfriend of 3 years in July. At the beginning of November his parents had some financial difficulties and came to stay with us to get on their feet. His Mom works (from our home on the computer), and his Dad (who has some health issues but is not incapacitated) sits on our couch (in our spot) in front of the TV 24/7. He doesn't work, doesn't clean, doesn't cook - he sits and gets served by the mom. They never go out, never give us time in our home alone. Our duplex has been monopolized. They have contributed no money to bills or rent. They are paying off some payday loans and storage fees, and still haven't saved anything - it has been almost 4 months! We are cramped into a duplex with them, their dog and their bird... and it's hard bringing this up to them (we've tried) because he pouts and she avoids the conversation. My boyfriend and I are both getting fed up - but he says I'm being selfish saying I want them out. They aren't helping themselves (sell belongings/car/him get a job), and my boyfriend is enabling the laziness. I feel so frustrated, I'm going crazy! What should I do?!