Personally thinking I think it's the other way around. I think that low self-esteem can be at the root of the feelings of jealousy and insecurity. Totally understandable with your background that when you let yourself love someone you worry that you are not their whole life, but of course as you already know that isn't healthy (or possible). I wonder what else you have going in your life? Are you happy elsewhere? Do you go out with friends and have a good time? Are you happy with work? (as happy as anyone can be working that is!).

Whenever I've got low self-esteem when other things go wrong in my life, or even that I do not feel like I am in control, I look at my partner for support, to be made to feel special, important because I look for him to fill the voids, to make me happy. All of the time. This is suffocating to him, and I understand that. Working on other area's of my life, sorting out any issues, making it richer (not money) has always, always had a better impact on my relationship. It's also much easier to believe that I am important to him when I have self-esteem.

Hugs to you, and I hope you find a way to cope soon. You clearly understand with your therapy, I just hope that you can find your own answers.