I've always believed that no matter how bad a relationship is, you can always learn something positive. This is what ex boyfriends have taught me...
A really handy shortcut through Victoria Station. I still use it to this day.
How to break into any council flat in central London. Hey, I was going through my bad boy phase. I didn't actually do any house breaking, I just know how to.
Wash up the cooking utensils while the meal is cooking. That way, you just have to wash up the plates and cutlery at the end. Unfortunately, this tip was the only positive thing I got out of that particular relationship because he slept with my friend.
Most importantly of all, never ever go back.