According to psychologists, many people stay in unhappy marriages out of fear or avoidance. If you are contemplating divorce, be honest with yourself about what is holding you back from making that decision. Are you worried you won't find another life partner? Are you worried about how you will fare financally? Are you worried what your family will think? Staying in a marriage out of fear is not a healthy way to proceed.
Personal growth occurs outside of our comfort zones. Whether that means trying something new for the first time or breaking a cycle of negative energy by leaving a marriage, you have to push past the moments of fear in order to reap the benefits on the other side. If your marriage contributes to your low self-esteem or insecurity you may need support from loved ones around you in order to make the first step towards leaving. The fear of being alone is very real but in and of itself is not a good reason to stay in a failing marriage.
If your partnership has been one of negative co-dependence wherein you lost your individuality and sense of self over time, ask a trusted person in your life for support during the process as you may have a difficult time being objective about your fears.
This is a great blog post from divorcedgirlsmiling.com on thinking through a potential separation. The essence of the argument in this post is that the moment you believe you are genuinely incapable of doing it on your own is the moment you know you should leave.