I am not asking about motivating the spouse. But your feeling when you at an event or in public as a known fitness professional and people see you with your spouse who is very unfit.
Fortunately, my husband is in great shape himself. But ultimately, it is not the shape I married but the person. I have witnessed it with other couples, though, that with the ‘shape shift’ there came a ‘mind shift’ which put a strain on the relationship.