I’m getting bored of it..?

So me and my bf has been together for 10 months, but I don’t know if I want to leave him or not because in my head I’m thinking, “oh you’ve been together for so long. Of course you love him”. But my heart just not feeling the vibes and I feel like our relationship is so dull. We have the same cycle every month like we’re lovey dovey, then we somehow become distant, then lovey dovey, and then by the time we’re about to make another month together I question our relationship. Is it healthy for me or dysfunctional? It’s hard because he loves me so much and I do love him..but just my hearts not in it. I wonder if it’s a phase for me or is it the right thing for me to let him go.?