Desensitization or exposure therapy can be really triggering, it can also be really healing. If you're going to do it I suggest at least being in contact with some sort of professional who is familiar with it. When it comes to something like jealousy, jealousy is a tricky thing. What helped me ultimately overcome relationship-wrecking jealousy last year was really kind of hammering it home that jealousy is a feeling, and everybody has it. I always used to assume that I was the only one and I was this petty, insecure, ridiculous person who wasn't worth the ground I stood on and that I should just shrivel up and die. Everything made me jealous or envious. But it helps to face it and be honest about it. That won't make it go away overnight or anything, oh no it won't. But it's a good start.
One of the best things I ever did for my jealousy was just stick around no matter how beaten down I felt by it. When I entered this relationship with my partner I felt jealous about everything: who she talked to, how many friends she had on fb, who was texting her, how she looked in a dress (way better than me of course), how short or long the dress was, how sexy she was, how confident she was. I was constantly suspicious. And so many times I just kept getting defeated, thinking, What's the point, I'm never going to get over this. I may as well just give up. But I knew that beyond what I was feeling this was an amazing relationship and I had finally met someone who loved me for me, saw me for who I was (even more than I can do with myself) and loved me BECAUSE of who I was, not in SPITE of who I was. So I stuck it out. I talked to so many people. What's jealousy to you? I would ask. When do you have it? How do you get over it? And I realized that even people I have always seen as confident, well-adjusted, sexy people with total control over their lives and destinies experience jealousy.
But for the longest time it was crippling. I would have to cancel plans to go out with her places because the idea of having to be in situations where my jealousy and insecurity would be triggered was just too much. And I know I hurt her feelings, and I hurt myself as well, but that's where I was at the time. But at some point, I can't tell you exactly when, it just stopped. All of it just stopped. I don't feel jealous anymore. She can talk to whoever she wants to, though sometimes I still feel a twinge of suspicion (I also have baggage from past relationships and my upbringing, which I also have to be honest about and own). She can wear what she wants. She can go where she wants. I don't feel threatened by everything all the time.
I don't know what the answer is for you. Jealousy's a tough one, I know from personal experience. It's possible though. Hang in there and just keep talking about it if you can.