In the OP's case the wife said "I love you but I'm not IN love with you."
It's time to go on the offensive when they start talkin' that bullshit,...tellum,..."Ya know?,...the exact same thought went through my mind a few days ago when I noticed how fat your ass has done got."
Then they gonna say, "Boo-hoooOOOOOOOooooo,...we need to see a marriage councelor".
That's when you say, "Nah,....we just need to hook a treadmill on front of the stove so you can be walkin' that fat ass off while you're fixin' my dinner".
