I have no problem with respecting myself as a person. I know I am intelligent, capable and caring.
What I am insecure about are my looks. I often feel like I don't measure up to societal standards of beauty. All of this stems from being picked on by boys in school and being told I was ugly. That still affects me even though now I get told that I'm beautiful/gorgeous, etc. I have a hard time believeing it. I accept compliments from people, but I can't believe it for myself.
It sounds like you need a healing program to help you deal with your childhood wounds. God has called us to freedom in Christ, not to live in bondage to the chains of our past. You could check out programs like Freedom Session....it's a healing and discipleship program, and really puts things into perspective.
Aside from that, you might want to examine your beliefs. We are not all called to social standards of beauty. Even when I am at my thinnest, I am barely average in the appearance department. For me, it really helped to examine my beliefs about God...how he created me using just the right mix of dna from both parents, how he "knit" me together in my mother's womb, how it would be an insult to God by telling him that he did not create me the way I would like according to my own ideas of beauty rather than his.
It took a lot of hard work to address this issue. It certainly didn't come overnight, but I had to really work hard on aligning my own way of thinking to God's way of thinking. He knew what he was doing when he created me.
Imo, if you do some work on learning to accept yourself, including your appearance, and examining what you honestly believe about God in the matter, learn to see yourself from his perspective....then you can walk into a healthy relationship with a healthy individual and when he tells you he thinks you are beautiful, you will believe him.
Until that happens, every time someone tells you they think you are attractive and you deny it, you are sending them a message that you think they are lying. Yes, it wears down on a relationship over time.
Develop your inner beauty. It has a direct impact on your outer experience...and when someone tells you that you are beautiful, thank them for recognizing the work of God in your life.