I took my ex boyfriends virginity and he took mine...?

It just sounds like a good thing that came to an end. It was probably an awesome four months, but now it's time to find someone else. He probably just needs time, too. I imagine he still thinks about you, regardless of how much he denies it. In time you can be friends. But what you need right now is space. Losing your virginity to each other is a huge, beautiful thing. That doesn't always happen. You both will always know that you have a piece of each other, and he's not going to forget it. Perhaps in the future you will be bestfriends, but for the time being you need space from each other.