Hardest choice of my life.

Emily
At the age of 11, I discovered that I was bisexual, and I had no problem admitting it. I have ever since identified myself as a bisexual female. I have recently gotten into a relationship, in which I am incredibly happy and so in love, and I am worried my identity is changing to polyamoros (when you feel the need for more than one relationship).
So basically, I had a crush on a guy about a year before I started a relationship with my current boyfriend, and I have recently discovered that he likes me. We got talking and I relised I have feelings for him again. (Also the guy knows I have a boy friend).
So here's the problem, I am incredibly happy and more in love than ever with my boyfriend. He is everything I have ever wanted. However, I am gaining feelings for someone else as well and I have no idea what to do or how to act in this situation. 
Do you think I am polyamoros? Do I tell my boyfriend? Do I tell the guy? Your advise is greatly appreciated.