Can someone please explain the song...?

this song is pretty easy to understand, but i like the meaning a lot. she meets this guy and right off the bat, without even knowing him that well, she has feelings him for while she has a bf and he has a gf. they start off cheating on their significant others, but then they break up, hence the..."Isnt this the best part of breaking up, finding someone else you cant get enough of?" shes saying she knows its going to turn into something big, something has to come of it, cause she thinks shes already falling in love.