Boyfriend vs. parents

Steph
I have been dating my bf now for almost 9 months and I have notice my parents don't believe he is good candidate for me, they say I deserve better. I feel bad because my parents and I have a good relationship and can talk about everything but now every time I mention my bf the connection between them dissapears. I have a long distance relationship with my bf and still they don't like the idea he stays with me in my apartment ( I'm 26 yr. old btw but my parents helps me with rent) when he comes to visit once a month nor I visit  him. I don't like to lie to my parents but they call me a lot and I don't know what to say. What should I do?