...what exactly do I tell my wife is the reason I failed to win the FreeBitco lottery last week.?

I am surprised to know that you tell your wife about these lotteries.

Surely it is a lottery and anybody can win or lose, although having more tickets increases the probability but does not guarantee one. Even a single ticket owner might be a winner if their ticket is a winning one.
- The lists of weekly users and winners are published from the very beginning and that is why you can produce a statistical analysis and offer it to your wife in a date that is important to her. Enjoy. Both of you.