I think many people would struggle if they were in the same situation as you are. This is not abnormal or rare. Jealousy is a common emotion but it can be destructive and you are smart enough to see the signs. I think it's brave and open-minded of you to work on your own issues and keep trying to be the best version of yourself that you can. You can't control other people but you can learn to control your reactions to them. I hope your boyfriend is understanding of your feelings at least. He doesn't have to agree but he should at least try to put himself in your shoes.

Based upon your own past experience with getting too close, it's understandable you would have some transference in this situation and it's a good sign that you recognize this and are working on controlling your own emotions and behaviors. I have a lot more I wish to say but I think I will leave it at that for now. Keep learning and growing. (((Hugs)))