How do you know if you are falling out of love?

How do you know if you are falling out of love or its just the end of the honeymoon phase?

I'm really confused and not knowing how to understand my feelings towards my boyfriend. I lately don't find him interesting or smart or even attractive.

He is also not romantic at all. He never surprises me or do somehhing fun for me. Our relationship is becoming very boring and I'm no longer interested in spending lots of time with him. The problem is I can't know how I exactly feel or put it in words. Are these symptoms of falling out of love? Or just something else?