Thank you for writing. I agree. If you don’t get hold of this, you’re going to lose a great guy. No one wants to live with this level of jealousy and distrust. It’s not fair to him for you to treat him like someone he’s not. And it’s not fair to yourself to hold onto the hurts from a prior boyfriend.
What you can do at this point is get yourself into some therapy. Medication isn’t going to fix these issues. Therapy will. You need help to recover from being betrayed and badly hurt. If you could recover on your own, you would have done it already. You’re clearly motivated. You just don’t know how to go about it.
Meanwhile, you can ask your boyfriend to put up with your behavior while you work on yourself. If he knows you’re in treatment, he may be able to stand it awhile longer — especially if you also focus on the good times.
I wish you well.