You need to take a step back and realize that this is something that just might destroy your relationship. That is, if you don't do something about it. It seems like you need to have a serious talk with your boyfriend. You have to let him know that you are feeling insecure. If you try to hold it all in, it will show in your ability to communicate with and be intimate with your boyfriend. If you share this with him, it will make you two closer. And when you decide to embark on your weight loss plan, he will be on board because he will know how important it is to you. Don't go it alone. I have tried the same thing with my husband over the years. It only makes it worse. Just be open and honest, and I'm sure you will be fine.