Oh Boy!!!
I totally can feel you pain about the jealousy, not trusting, self-esteem in relationships.
I was with my now ex-husband for 10 years (we started dating at 20, married at 30 divorced shortly thereafter) and up until now (im 32) I have never had any jealousy, insecurity, nothing. With regard to the trust cheating thing he was no worry at all. We never had any problems in that area. Things deteriorated a while before the wedding but I was too much a coward to end it, I thought It would get better. It didn't and I ended up cheating on him, with someone I knew, a friend and it grew into love. I ended my marriage and am with the new guy. I know, all readers are cursing me and hate me, but if I could go back in time I would change everything (how much i hurt him, everything, I carry alot of guilt and so I should - its the least I deserve for being so horrible).
I am about 1 1/2 years into the new relationship, which is plagued by mistrust, jealousy and insecurity. I know it stems from what happened but I am so mistrusting of my new guy its brutal. Even though he is hasn't cheated on me reassures me etc. Sometimes with the jealousy thing, because of stuff that happened to us before, we can ruin relationships with insecure bull****.
If your guy is not doing anything to make you jealous and you know its all you...you really have to get a hold of yourself. I know its hard and all-consuming and draining to go through the insecure bull****. The fact that you are in therapy is fantastic, you realize you have jealousy issues. But you have 2 choices, try to get over this or leave him. I know you know this but in black in white thats what u have to deal with.
In these kinds of realtionships you do lose yourself, I am losing myself as we speak. The only thing that I know I should do is find things to do independently or with other people, not the boyfriend. Doing these things improves self-esteem which is the culprit of jealousy. Make yourself feel GOOD with out it having to do with him. Go to a day spa (if u can), have your nails done. Anything that YOU want to do to make YOURSELF feel better.
When you said that sometimes you think "if I don't trust, I can't get hurt" I almost cried. Thats how I think too.......I feel if my guard is down then most certainly something bad will happen. My boyfriend says that I won't let me be happy, if things are goin' good I wait for the bottom to fall out. He's right.....and that sounds like you too.
I am also trying to find ways to get over this and live a happy life but its hard. I am doing things for me, now, and it seems to be working a little bit. I take it day-by-day and that helps me.
Good luck!!