A sad but great song no doubt. The meaning is pretty straightforward. This song is about two destructive people in a destructive relationship through no fault of their own. For whatever reason, each have commitment issues because of their upbringing. "Daddy issues" can pertain to anything: lack of love, emotional validation, or attention - or even abandonment. Point being, the father figure was abusive in both of their lives in some way, causing them to be the way they are today: messed up. It's like two soggy pieces of a puzzle that try and mesh together, but they were never meant to fit, it just appears that way, and the sogginess will keep them glued together temporarily, but the connection is destined to fail from a lack of strength on both parts. The singer can empathize with her pain (or can he?), but ultimately they will never be able to engage in a fully healthy relationship. I like the "let it out" part, though. You have to, otherwise you can't grow.

So the moral of the story is that “she knows”. The rapper may be out playing his little romance games, screwing around with other chicks behind his real girlfriend’s back. But “she knows” nonetheless. So the penalty is that he too has to go about wondering if his true boo is messing with some other dude(s) also.