body type the problem?

Options
I have an odd question, but I don't really know if it is the root of the problem or not....

I was always "thinner" until I had my daughter when I was 32. Before, I never weighed over 135-140. After that, I have been overweight almost the entire time. My highest weight was about 18 months ago at 230.

I have been told by doctors over the past 10-12 years to "lose weight". 10 years ago I started at 190 pounds and while I did get below that for a brief period years ago, I have mainly gone up, instead of down in weight. When I do lose any weight, I always get back to this 190 pound mark and don't seem to be able to get below it regardless of what I eat or the kinds of exercise I do.

I am finally back to the magic 190 pound point (my goal is 140-160, which is what BMI calculators tell me is a good weight for my height and age) but haven't lost any weight in the past two weeks in spite of the fact I am eating exactly the same as I did the previous two weeks when I lost a few pounds, and I try to keep exercise "rotating" so that I don't get accustomed to only a particular set of moves.

What is it about the 190 pound mark by body does not seem to want to move beyond? As mentioned, this isn't the first time I have gotten "stuck" at this same weight and it not only becomes discouraging, but then I start putting weight on again. Is there something about this weight my body likes? It sounds stupid, but I just can't figure out why after a number of times trying to lose the weight I get stuck at the same spot every single time....

Anyone had a similar experience or know why this continues to happen?

Thanks!