What do I do?

Katie • Here to track my period and sex life.
Long story short, I'm almost 19. I'm starting school in August. Moving away from home. Met the love of my life last year and we plan on getting an apartment together. As it will be over a year of us together when we plan to get it. 
My parents call me immoral and slutty and ask me where they went wrong with raising me for thinking that it's ok to live with your boyfriend before you're married. But they're my parents and I wish for their approval. As I didn't have a very good childhood I've always seeked their approval and their support, but have always failed to receive it. 
My heart and my mind are set on moving out in August as I hate being stuck here with them. 
But if I live in a dorm instead I will make them happy with me and find their approval, however I won't be happy. 
But if I move out with my boyfriend I'll be the happiest girl alive and they'll still think bad of me. 
And I don't know what to do. It's like I'm stuck between and rock and a hard place. Do I do what they want and make them happy? Or do what I want to make myself happy? 
Ultimately it's my life and I should do what makes me happy? Right?