You are right when you say this on base of cold logic.
But dear PCG I think you never fall in love, it is love which dictate someone to go extra miles.
When Spiral express loves for her husband, forgetting her own pains trying to give her best for him. It is not stupid, she is not becoming maid but it is expression of pure love, and i am sure the husband understand and appreciated that as well.
Whether you buy it not but i would certainly appreciate and proud of my daughter if she has that kind of love and care towards her hubby.
Great! And it goes both ways, husbands go miles extra when they love their wives.
There no lines to draw, instead, much of an overlap of each other's so called boundaries.