Most Helpful Girl
Not only that, but I would go directly to that girl and let her know her boyfriend has wandering eyes and that she needs to seriously watch him or dump him. I can't stand people like that. Signs of being unfaithful.
Most Helpful Guy
You are 17, so I wouldn't ignore it. This might sound bad, but who said she really likes the other guy? It's called being to young to know what love is. As an adult though you want to just say to the girl, "you already have a boyfriend" or even worse for me... "a husband"