I love him but I have a crush on her

I’ve been with my boyfriend for two years and a little now. I’ve never been with a girl but I’ve had feelings for girls in the past. I’m 20 years old and I don’t know what’s come over me. I find that whenever I’m alone all I can think about is this girl who I’ve know since high school and I don’t know if it just because I’ve never had the courage to tell anyone about how I might be bi or gay or something that’s not straight or if I’m just over thinking. I don’t know I’m so in love with my boyfriend he helps me out so much and I wouldn’t change our relationship for anything but this girl is all I can think about when hes not around. I don’t know if I’m being unfair staying in this relationship with him but I love him and I don’t want to let him go but I’m also so curious to see how life could be with her. 🤦🏽‍♀️🤦🏽‍♀️