If you keep your body in reasonable trim then I and many men would consider you beautiful enough to be highly motivated to want to make love with you. Regardless of your facial bone structure and complexion.
And then there's inner beauty. Which you can enhance a small, but significant bit by accepting your looks and proceeding with your life with positivity and enthusiasm. With you accepting that you may not have the most traditionally beautiful face but you do have a beautiful body and personality as well as a collection of other positive features, such as ability to earn money. And therefore any man that gets involved with you will have gotten the joint best girlfriend / wife in the world.
Also, bear in mind that people say all sorts of cruel things in the heat of the moment. Many of which aren't true, or are exaggerations.
And that beauty comes in many forms.
Focus on the positives, not the negatives.
Never talk yourself down.
I cannot agree with the overly negative and critical mindset of your parents. It's like they want you to become a timid adult lacking in self confidence. Which I think is evil. Because they should be aiming for you to become a fully functioning, independent, well adjusted adult.