How to fix the contact list on my iphone?

My Boyfriend accidentally synced his contacts to my iPhone, so when I logged in, mine got synced with his and somehow got multiplied. Is there a possible quick fix? Is there a way to do this from my itunes? I want to keep my contacts, but delete all of his. I'm not a whiz with Apple stuff, but get the basic gist of it.

I would call the apple customer care number and ask them. It seems like a big issue, and I've never heard of this happening.