I need help on telling my husband that I want to be a vegan and be healthy

So my husband is against me losing weight. I want to become a vegan again and just be healthy. I think it is because when I do lose weight I get attention from all different kinds of people but I am not doing it for them. I was adopted so i do not know my family health history. He gets very jealous when I want to do something for myself. So he got his haircut and he loves all the attention women give him and he is losing weight. I just want to do it for myself because when I was smaller I had more self confidence and I just loved myself. I do not know what to do about this?