Falling out of love?

Has this happened to any of you? I have been with my BF for 7 years and I'm starting to "fall out of love". I feel terrible... I don't know why or how to tell him. Why does it happen? I. So depressed over it. 
I want to remain anon.... But he doesn't want to get married, I'm ok with that. Also, I'm starting to like other people but never acted upon it. Haven't even been talking to anyone else so it's not that I even want anyone else. I'm just bored... I feel nothing. 
*we also have a on year old baby together.