I actually bought mine before I was even engaged. Yes I know how ridiculous this sounds.
Basically I knew who my BM's would be, and I had an idea of the style I wanted. I was on the Debenhams website and the exact dresses were reduced from £120 to £36 each. When an email popped up with a 10% off code, I thought s0d it, and bought them. I had an idea the proposal was on the cards (we were off on a Hols of a lifetime and he'd taken a day off to spend 'gardening' with my dad).
If they lose or gain weight, get pregnant or whatever, it's not as if I'll have lost a lot of money.
I did tell him the story, he loved it.
Let's do it. Let's go get the sh*t kicked out of us by love.