I think the answer lies in facing yourself and finding out why you feel jealous and insecure. If enough people have rejected us, we begin to "assume" others will, and they usually do, for we have already rejected ourselves through the perception we have of ouselves.
If you pick people in your life that try to control you or aren't kind to you, then there will also be a continuing internal feeling of being unimportant and you then become jealous of other people because you feel insecure and perhaps don't feel you measure up.
Loving yourself is always the key to having the confidence you need to accept nothing less than the best for youself. You then won't have to feel jealous or insecure, for you know who you are and what you have to offer.
I used to feel the way you say you do now.
But, I now believe in a God who loves me and who I have accepted in my heart, and this has transformed me into a woman who finally knows what love is, and this gives me a confidence and a strength to no longer make wrong choices which leave me feeling insecure or jealous.
"In the fear of the Lord is STRONG confidence."