Sometimes out of love parents think they are helping when they are doing the worst thing possible. Your parents only want the best for you, but they are going about it in the wrong way. You are a 20-year-old woman and they are treating you as if you’re half that age.
It is time for you to talk with your parents about their conversations about your boyfriend. Explain to them that what they are doing isn’t making you like your boyfriend less, but actually making you feel more distant from them. Explain that just because they think he isn’t right for you doesn’t change how you feel about him, it only makes you wish they understood your needs better. Finally help them understand that you know the same things about him they do, and that you are willing to make the choice knowing who he is–and who he is not.
I do not think this is easy. I think the process of growing up in general is difficult. Part of what has to happen when you individuate is to let the people who love you know you appreciate their help and their advice and you will consider it, but that in the end they have raised a strong independent woman and you will be making your own decision.