It’s An Ugly Truth: The 8 Most Common Reasons People Cheat
But you can’t fix that person
If a person is so unstable that they would fall into a deep, debilitating depression, or hurt themselves if left, you’re not helping them by staying with them. They were going to have a breakdown sooner or later, if not because of your leaving them then because of something else. You should never live in misery just to hold somebody else up. If something terrible happened should you leave that person that is not your fault. You are not a therapist. You’re an individual deserving of a healthy and happy relationship.