Past relationships can be a sensitive topic to discuss with your girlfriend. On one hand, being open and honest about yourself can provide the foundation for a stable, healthy relationship filled with trust. On the other hand, going into vivid detail about your romantic past can be awkward and for some may be seen as opening Pandora's box by revealing too much information about previous girlfriends. While sharing your past is not a prerequisite to maintaining a relationship, as your relationship evolves it is normal to open up and share more of your relationship history.

The Strength of Disclosing Your Past

Being open and honest about your past may be one of the most fundamental building blocks to establishing a long-term relationship. People tend to trust and feel attracted to those who self-disclose personal issues as opposed to others who are more guarded about their past, according to a 1986 study conducted by researchers from Southwest Texas State University and CIGNA Healthplan of Arizona and published in Social Psychology Quarterly.

Tactful Disclosure

How you reveal information about your past to your girlfriend can also play an important role in your relationship. If you and your girlfriend are planning a weekend trip to the beach, it is acceptable to mention that you visited there once with your ex-girlfriend, but discussing your past romantic sunset picnics borders on being untactful and rude.

Too Much Disclosure

Just as withholding information about your past can have adverse effects on your relationship, talking too much about your ex may also prove to be problematic. You should focus on your current girlfriend during the initial stages of your relationship to avoid carrying too much old baggage into your new relationship, according to psychologist Allison Conner in "Top 10 Dating Mistakes" for Psychology Today.

The Right Time and Place

At some point, you will begin to reveal more details about your past to your girlfriend. While you may want to refrain discussing what caused the end of your previous relationship on your first couple of dates, as your relationship starts to take a more serious turn, talking about your wants, desires and hopes for your relationship, and how previous relationships did not satisfy those needs, may become an appropriate. You may also want to find out what went wrong in her past relationships so that, together, you can think about how to make your relationships stronger.