Most Helpful Guy
It's not all that odd for people to feel something for one another after a break up. That is usually why they delete that person from their lives so that they can forget them since there will always be those memories and feelings. It just doesn't end that easily, it takes time to fade and even then it might not totally be gone. People always go through stuff like that, so don't be surprised you can't forget all that easily, and also, just to keep in mind, it doesn't mean that he is solely the only person for you either.
Not to rain on your parade, but dedicating a love song or saying "I love you" aren't exactly unheard of within relationships. I mean, personally I have done both those things, although with sincere motives, it doesn't mean that no one else has done so, and couldn't have. I can't say anything for sure because I don't know you, him, or your relationship in general, but by how much I've seen and witness this within relationships of friends, family, and acquaintances, that people use "love" a bit too loosely. I'm not saying he doesn't love you, but perhaps it isn't a genuine unique straight out of a fairy tale love, after all, he flirts with you despite liking another girl.
What I am trying to point out is that, you can make whatever choice you want, but don't simply let yourself be taken by your emotions alone. You need to think rationally on your feelings, your wants, your thoughts, and what is better for you, and that means to question all these things and him. I mean, you believe you love him, but do you think he is really the one, or is it possible that you can love another? It's never easy, specially depending on how much time and effort you put into the relationship, but you'll back at an experience like this and learn from it, be it by the decision in favor of him, or getting over him. I don't know if you'll regret the decision nor which decision.
You make what you want of it all. These are just mere opinions of a complete stranger.