I’m really bad at "thou shalt not covet". I get very upset when others have or earn more than me. How do I stop?

I am a very pleasant person to people around me, deep inside though I am very envious, specifically of a certain close family member who has everything I don’t and in some cases can’t (I have a medical condition whereby I can’t have kids, they however have beautiful kids, I struggle with work and they make top 0.1% income, etc). I love them very deeply with all my heart, but get so upset by feeling inadequate that I actually feel suicidal sometimes.

I know this is a really bad trait and I have been dealing with it for almost my whole life. I hate that I feel this way, I feel like my whole life is a competition that I’m losing. I really would love any advice on how to stop this awful character trait. My days are eaten away by jealousy and bitterness; towards someone I love dearly and whom I hate to have these negative feelings aroused by.

Thank you for your time