Jehnifer, I had a similar problem, and one thing I had to look carefully at was my fantasy life.
I could not stand there and tell anyone what I wanted, but I knew the jealousy I'd feel when:
--Someone talked about how happy they were with their husband/wife, and why
--I saw a movie where a couple was really great with each other, really strongly bonded
--I read novels where a man said to a woman the things I wished someone would say to me, or where they did things together that I just knew I could never hope for
--I hung out with friends and saw the kinds of things another couple would do for one another
My jealousy, in a sense, became my map. I couldn't articulate it for myself, but I could see it clearly in other people.
And I had to tune in to the small voice inside me that would jump in and criticize me if I ever wanted anything for myself. That voice is horrible...and so hard to hear, but it's there. As soon as I see one of my jealousy triggers above and think, "Wish I had that," it would jump in right away, almost like a kneejerk reaction, to slap my hand, tell me I expected too much, tell me I was daydreaming. That was the voice of my father, I now know, but that's another story.
And one thing I discovered through counseling too: Although I would never admit it, I was looking to my relationship to be my sole source of happiness. If asked to make a list of 20 things I loved to do, for me, with or without anyone else around, I couldn't do it. How could I know what I wanted out of marriage when I didn't even know what I wanted out of life? Marriage to me now is part of a larger plan for my life here, full of things I want to do and be over the course of these few decades of life I've been granted.
I found the books of Barbara Sher were really helpful in figuring out what I wanted out of life, also Jennifer James' book "Women and the Blues" has a lot of material on the things we crave and how to discover and honor them.