What about situations where both halves of the couple are in a rut with things like sedentary lifestyle, bad eating habits, becoming potatoes rooted to the sofa, not getting out socializing, etc? Let's say one partner goes to the doctor, the doctor warns trouble is on the horizon if some changes aren't made, partner takes it seriously, goes home and shares the situation with their spouse and begins to make (sensible) adjustments to avoid a health crisis. Spouse may even say, oh yeah, we should do something, yet won't follow through and as time goes on begins to grumble because their partner suddenly isn't content with pizza for dinner followed by ice cream and their favorite shows, instead choosing to go for a bike ride after dinner or take the dog for a walk. Maybe the mate who doesn't want to change their ways is even battling depression and their anxiety is causing them to get angry their partner is "changing the rules".
If the spouse making the lifestyle change isn't forcing their mate to make the changes and isn't actually refusing to spend any time with their spouse, should the spouse making the healthier lifestyle adjustments be forced to go back to unhealthy living, or should they just keep encouraging the reluctant partner to make some small adjustments? It's not uncommon for one spouse making healthy lifestyle changes to face backlash from a reluctant mate -- and for the balance of the relationship to be thrown off.