Is excess fat unattractive?

I know that fat is unhealthy but is very much of it unattractive? Almost 
everyone I know is heavy and dieting, and I don't have any slender 
friends to compare myself with. Models and actresses are usually slim, 
but most regular people are not, especially where I live.

The problem is that my boyfriend seems to be losing interest in me. When 
we started going together, I was 40 pounds lighter.  The prospect of 
losing him would motivate me to lose weight which my doctor wants me to 
do because my triglycerides and bad cholesterol are high and so is my 
blood pressure. My good cholesterol is too low.  My doctor says I'm on 
my way to having diabetes and that I'm pre-diabetic. I'm 35 years old 
which is too young for this.

None of the health concerns have helped me to lose weight. I know they 
should, but the idea of losing my boyfriend would make me stick to a 
diet I think.  The trouble is...I don't think he's honest enough to tell 
me whether my weight is why he seems to be losing interest.

I think I need to hear it from others, but even my family says I look 
just fine to them. Trouble is, they're all heavy.

I'm 5'2"  and 175. I used to be 135. All my boyfriend and I do for 
entertainment is eat out and go to movies. He works in a lumber yard and 
gets lots of exercise, but I work in an office and sit all day.

I love pizza, Cinnabons, chocolate, fries and donuts, and the more I 
eat, the more I want. I live at home with my parents who have similar 
eating habits.

Any advice would be appreciated.