I need relationship advice

So is it normal after a certain time of being dating someone to just feel very casual and calm, kinda boring or something like that. It’s not the same passion as the beginning, and it’s making me worry I’m crying myself t sleep because of this I’m scared I don’t love him anymore even though I cry to the thought of ending things with him. So I’m not sure if eventually things get casual or something. Also to clarify I have ocd wich may or may not be the cause of this.