Confused...

So I love my boyfriend dearly but he can be clingy. He is the sweetest guy ever and does everything he can for me but I catch myself thinking about my first love a lot. Like if my boyfriend does something that reminds me of my ex all I think about is my first love. I don't ever act on my thoughts and I never text my ex I just think about him a lot. I tend to look at his Instagram and snapchat to see what he is doing. I don't want to hurt my boyfriend because he is the most amazing guy and would be a wonderful guy to someone and he is to me but it's very hard to focus on my boyfriend and I's relationship when I'm thinking about my first love. I know there isn't a future with me and my first love. I was a freshman and he was a junior, I knew it was never going to work. He gave me the run around about he needs to experience life. I lost my virginty to him and everything. I just want to know how to get over my first love and stop thinking about him so much?