You are missing out because you have a partner who is insecure. Jealousy comes from insecurity. Especially jealousy that isn't based on cheating. You have to decide if you think over time she will be more secure in the relationship. She is obviously struggling with severe insecurity. This may be based on old hurts. She can be taking pain and projecting that onto you. Her fear of being cheated on is greater than her ability to trust you. This is causing her to act out in an effort to prevent you from doing what has happened in the past. This causes her to act irrationally. You have to make a decision on whether you want to tackle the problem of helping her get over her insecurities. There is also the chance that she may not do so. Tell her that you will help her get this problem under control but she has to promise to work on this. It isn't fair to project these fears onto you. Then when you think there has been sufficient time decide if the relationship is better. It's your decision.
Please press accept; this is the only way I am compensated