I think this is about a relationship that is completely physical, but he ends up falling for her gradually. Typical friends with benefits type of cliche. As he says he is "tongue tied over three words", wanting to tell her how he feels but afraid to ruin what he has. However he knows her better than anyone else and knows that if they could start over as a proper relationship, he could help her and "mend her broken heart"
I think this is about a relationship that is completely physical, but he ends up falling for her gradually. Typical friends with benefits type of cliche. As he says he is "tongue tied over three words", wanting to tell her how he feels but afraid to ruin what he has. However he knows her better than anyone else and knows that if they could start over as a proper relationship, he could help her and "mend her broken heart"