Don't beat yourself up about it. I went through something similar and made a lot of the same mistakes of ignoring red flags and questionable moments that I KNEW were bad because the good times were so damn good. "Narcissist" gets thrown around a lot these days to describe anyone who's an asshole but it's rare that you will encounter a true, clinical one. Narcissists literally care about nobody but themselves. Any concern or whim they display for someone else is a contrivance to manipulate them into doing something they want or getting something from them. They mimic emotion and romance and tend to be very grand about it. At first it makes you feel special and loved and wooed and all that, until like you experienced, it becomes apparent that it's all bull and they're doing all of this to manipulate you.

I'm sorry you had to experience the misery that is dating a true narcissist. Mine ended four years ago and I'm still dealing with the issues it caused with my sense of self worth and judgement of character. The GOOD thing about this is now you know what to look for and you escaped without any permanent tethers to him like a child.

Good luck OP, be kind to yourself, and be glad you're free of him.