the first ending you never wake from your nightmare and are committed to an asylum for the rest of your days. You never overcome the grief and remain trapped in your own world. You are a child at the end running from your problems symbolized by the dolls (your daughter). You kissing your daughter at the end symbolizing you not accepting reality and continuing to live in your own torturous dream.
The second ending shows a pretty dark path. The woman who appears dead over and over is symbolic of you taking your grief out on your wife after the death of your child. You never move past the grief and act abusive in some way towards her. Throughout your journey you get committed but "get better" and return home but continue to grieve causing problems for her. Eventually you get the ending where your wife loves you but she's had enough leaving you to your own nightmare alone.
The 3rd ending is likely the "good" ending. You have the symbols of the Wife and child but show a 3rd as well. Just like in the other 2 endings you get admitted to a hospital. At some point you attempt suicide but fail to kill yourself. In the nightmare world you encounter the true demon, Yourself. By avoiding this demon and pushing past it you "overcome" him and move past your nightmare and wake to your wife in the hospital alive.