I'd ask the soon to be wifey how she sees it. You'll soon be sharing assets anyway so no time like the present to start sharing.
I'm not married but I am living with someone. We always talk about big purchases. Don't think I'd like it if he risked all our wedding money. Especially without me knowing about it. But, I'd probably have no problem with part of it for the right play. Not that I have any idea of what your relationship is like.
But, FWIW I'm the super supportive girlfriend that always tries to find a way to get him everything he wants. Even the sportcar or the motorcycle. Maybe he can't get it today but I always find a plan to make it happen.