I was the 'fat spouse', although my dh has had a bit of a gut, even when we married. I was a 115 lb size 3. After a couple of kids, I gave myself license to balloon to a 190 lb size 18 (I'm 5'2" with a medium, muscular frame). This has been over a course of an 18 year marriage. My oldest is a teen now.
In the last year, I quit making excuses and kicked my dependence on food and have lost 60 lbs. Even though I'm 130 lbs, I'm a size 4 and a lot more muscular than I was at 18, so getting back to 115 may not be possible (carrying around extra weight made my bones denser maybe? or gave me more muscle?). I'd like to shred down a little more; maybe lose 5-7 lbs.
Anyways, I lift weights, do interval training, biking, Crossfit and I love running which I do 3-4 days a week.
On the rare occasions over the course of my marriage when dh would complain about my weight, I'd cry and do the 'but don't you love me for me...blah, blah, blah.' I started reading Dr. Laura and what she said in one of her books to a woman who thought her husband should be understanding about NEVER getting sex was, "Why should your husband be sanguine about the lack of intimacy in your marriage? Why did you two get married?!" So when my dh said, "Am I going to eventually have to roll you around in a wheelchair? I didn't sign up for this!" it hit me. I heard Dr. Laura's voice saying, "Why should your dh be sanguine about the fact that you're a glutton and a cow?"
Coupled with the realization that I had the same problem with food that dh had with alcohol, I was disgusted by my own weakness. So this year I finally did something about it, by severe calorie restriction, a nutritious diet and exercise. I always hated how fat I was, so why should I expect my dh to accept it?
Interestingly enough, my dh needs to lose 50-60 lbs but he looks the same to me as the day we got married (although when I look at our wedding pics I know this is not true). But he's always been a serious lifter, very tall and very muscular and I like big men (not fat men, just 'big'). I care that he loses the weight for his health and so I can stop listening to him bellyache about it.
Reading the viewpoints of the 'fit spouses' on this site helps encourage me to keep going so that I don't make my dh feel that miserable again; which is worth it because I love him. I also feel better in dozens of ways including feeling sexier and I'm setting a better example for my kids.