your comment is great.
I was think the same thing but in less funny terms.
Also there is the question the likely hood the MC knows or thinks his bride knows martial arts. If he thinks that bride is "normal" then the old mans argument does not hold any water. His bride would than never be on the front lines.
I just hope the bride isn't someone annoying who complains and argues 24/7. I hate those romance stories so much when she is just an annoying character but stays because she's the mc "waifu".