I would tell her. Youíre damned if you do and damned if you donít. Suck it up and tell her. Besides, if youíre almost married, youíre never going to get any after you get married anyways... so you might want to get used to it
"(name here) I lost some of our savings. It was a mistake and I promise I will never do it again...
..now please stop beating me"
kidding. If a relationship has elements of fear, distrust or anything negative or hidden, it's really not deep. For a relationship to grow, both have to open up and be vulnerable. It means being honest to each other. It also means that both have to work on creating an atmosphere where one can talk, else both will always have the fear that they cannot say the truth cause the other is going to flip which will cause both, you and your partner to hide things from each other.
that is not a deep relationship. One that one you would not want to have with your future wife.