Establishing boundaries with a person you were taught to share everything with can be difficult. As children, you did everything together, shared your belongings and kept each other's secrets. The dynamics of this sibling relationship can be impossible to maintain as adults with separate families, careers and relationships. Establishing healthy boundaries with your sibling will ensure a respectful, caring and mutually beneficial relationship.

There is no magical formula or correct answer to the amount of involvement you and your sibling should have in each other's lives. The key to a healthy relationship is to establish boundaries that you are both comfortable with. Take some time to reflect on how involved you would like your sibling to be in your life. Ask yourself if you want to see him only on holidays and special occasions or if you'd like him to be in touch every day. Make a list of what you like about your current relationship and the things that you would like to change. Ask other close family members or friends for their opinions on your sibling relationship. Does it seem like a healthy relationship to them? Do they agree with the things that you would like to change?

Schedule a time when you can meet with your sibling individually with minimal distractions. Talk to your brother or sister about your reflections and the need to establish boundaries. Be specific regarding the amount of involvement you want him to have in your life and how much he can expect from you. Give examples of times when you felt uncomfortable or overwhelmed. Use 'I' rather than 'you' statements to avoid conveying judgement or blame. For example, you can say "I need some private time with my family and would like for you to limit your stays to a few days." Give your sibling enough time to share his own perspective.

A big contributor to an unhealthy sibling relationship is having weak personal boundaries. Yes, your brother or sister is taking advantage of your generosity by staying in your home for months, but you are contributing to the situation by not being firm and communicating to him that the behavior is unacceptable. Practice being firm when you communicate. Establish clear personal guideline and abide by them. Push aside guilt or pity when someone is crossing your boundaries. And, always keep your personal well-being a top priority.

There are times when crossing sibling boundaries may be necessary. It is completely normal and healthy to become more involved with your brother or sister when either of you is going through a rough patch. A 1992 study, "Life Transitions and the Adult Sibling Tie: A Qualitative Study," published in the "Journal of Marriage and Family" found that siblings become closer when one faces a divorce, illness or significant loss. Be open to change in the dynamics of your relationship when a significant life event occurs. Be patient and allow some time for things to shift back to normal.