1. Comfort
First of all. I'd rather lay on a stomach that can mold to my head. Abs are too hard and not too comfy.
2. Self Esteem
You can eat whatever, whenever you want. Plus, there's no pressure to go to the gym. Also, personally, they'd definitely have larger boobs than I do. There's no pressure having to look flawlessly.
3. Finders Keepers
There's no surprise when he puts on a little weight as time passes. With all that food you're free to eat, it's inevitable.
4. What competition
In all honesty, girls get pretty insecure when other girls stare at their mans. If he had abs for days, I'd feel like I'd have to keep up with his looks for days - you feel?
5. FUN
They're usually more fun. They're not busy going to the gym, instead, they're down to order in, watch netflix, and call it a night. They're always down to incorporate food, and THAT'S always fun. Binge drinking is always an option. They're also usually funnier too.
6. You First
You might not come before his mom, but at least you know that you come before the gym does.
PS: Guys with higher BMI's last longer in bed, so there's that!!