He needs more personal space, that the partner can offer. Of cause leaving the other person means to hurt him or her and the feeling of not beeing able to breath is because he feels trapped.
'I don't want to hurt you but I need to breath'. The promis you always give somehow getting in a relationship. He means the promis to love and stay by each other for the rest of their lifes. 'Youn know I'm not one who breakes promisis'. I think it's about feeling overwhelmed by his partner. I don't think it's about beeing friendzoned.
