Some women's libido goes down from the stress of seeing a lot of chores needing to be taken care of. Doing those chores reduced the stress. Going further and doing what is normally their share of housework can be an act of affection.
It's also noted in a study of women asked to rate a number of pictures of men on various factors including attractiveness and reliability. When they are also asked for dating preferences, as the age range went up, the prioritization on reliability ratings also went up. Doing chores is reliable AF.
More to the point, she's already told you she likes it. Just believe her.
There should be no illusions about resisting an attack. That's not really possible in the modern transparent battlefield. All fixed defenses are struck in the opening salvo, AA defenses, radar networks, airfields. China would take immediate air superiority. Amphibious assaults are ridiculously dangerous, nigh impossible, but every shot fired in defense receives immediate retaliation from the air. This is different from the war in Ukraine where there's contested airspace instead of one-sided superiority. Mines will slow the landing but without the ability to resist it, its just a matter of time. Deterrence needs to be economic and political, a military deterrent is not going to work on the doorstep of a world power with anything short of nuclear armament.