I think it's important to remember to never lose yourself in another human being.

Never become so reliant and dependent on another person that you cannot function alone. Never become so wrapped up in who they are that you lose sight of who you are. And don't ever, ever get into the habit of repeatedly sacrificing what you need to give someone what they want.

And if you find yourself there.. I hope you have the strength to know that staying will hurt worse than leaving.