You’ve learned a hard lesson about what lies and avoidance can do. Your folks are understandably upset. What started as concern for you has morphed into a major reaction to what they see as a betrayal of all they stand for. You may have thought you were doing a romantic thing by moving in with your boyfriend but you only demonstrated to them that you are immature.
Unfortunately, no one is currently acting like the grown up they are, including you and your boyfriend. The two of you owe your parents a major and heart-felt apology. I hope you can remember that your parents’ concern comes from love. Your parents owe you the respect to listen. I hope they can remember that they didn’t raise a stupid person.
Hopefully you all love each other enough to find a way to find a “re-set” button. If you don’t think you can handle a frank conversation that will require some compromising, think about whether involving a family therapist or mediator or a priest you trust might help.
The stakes here are high. Marriages where someone like yourself feels she has to choose between the people she loves often don’t last.
I wish you well.