Jealousy shows us that we feel threatened. Often, this threat manifests as fear of losing something, therefore we are possessive.

Sexual history jealousy (often known as Retroactive Jealousy) is telling us that you are possessive around your girlfriend. Part of you is trying to keep her to yourself, and so you see her previous experience as a threat to that.

We could extrapolate this out, and see that some part of you believes that her previous sexual history somehow indicates that she could be perhaps more interested in other men than you, and therefore be stolen away at some point.

Or, you could think that her history somehow diminishes her enjoyment of you, and therefore is a threat to the relationship.

To dive deeper into this topic, check out the original video here: