[anonymouswhale]

I will be honest with you. It's very, very difficult to have a best friend of the opposite gender while you have a significant other. At least in my own experience, jealousy becomes a big thing. People can be possessive over their loved ones.

Think about it from your girlfriend's/her ex boyfriend's perspective. You two once loved each other, kissed each other or did anything that would be emotionally close to one another. If you were together in the past, what's preventing those feelings from resurfacing?

People get worried about that. It's not really you they're worried about- it's the best friend. So, he was worried about you wanting her back, and your girlfriend being worried about you wanting your girl best friend.

It really is a simple explanation in my opinion. People lose confidence and begin to get trust issues. In their minds, "Why would they want to hang out alone? What's happening? Am I going to get cheated on?"

Just wanted to possibility show it from their perspectives.