What "I" get from it is:(and this is NEVER having seen the video, and just going from the lyrics and emotion) this guy and his girl are struggling in their relationship. He promises he will change, but as we all know Tigers rarely change their stripes. He is who he is, even though he WANTS to be good for her. In the background after the verse "we're gonna make it all right, but not right now...I know you're wondering when..." there is the verse, almost a whisper, like it's coming from inside her "you're the only one who knows that"... meaning she can "make it alright" by leaving the relationship. It's toxic. No matter how much love they have, it's just not going to work and to "make it alright", "when" is determined by "when" she makes the hard choice to leave the man she loves for her own preservation.