Losing love?

Ive been with my boyfriend for about 3 years, I deep down do love him. But lately I havent been feeling it. I don't feel romantically attracted to him and I feel as if he aggravates me more than anything. We dated when I was 16 and im almost 19, I think its because im in a totally different mindset and I feel like our relationship is so much work. And yes ive tried to talk to him about it but he doesn't understand. Help please I need advice!!