Spoof, just get a spare blade that you keep with you tying stuff. When you use your wife's cutter it is simple and quick to swap blades and it will do no damage to the mat or cutter no matter what you cut.
I have several blades for mine, 1 with Cub Scout stuff, 1 with tying stuff , 1 on the tool bench and of course 1 for fabric that way I never destroy 1 without knowing that I am probably ruining that specific one.