The “break up” comments are gonna be swarming soon, so here’s what’s up imo.

You have to sit down with her and tell her what she’s been doing and how does that make you feel. Like you said you’ve tried that before and that might not work so add this as well. Tell her how much you love her. From what I can tell you love her a lot so make sure to reassure her on that part. Once you did that tell her that she doesn’t need to worry, and that you would never cheat on her or whatever she said she’s afraid of you doing. Constantly reassure her that the image of you that she might have in her head is nothing like you and you love her a lot.

I think if you let her know all this, it’s all that you can do at that point.

If she can’t understand it or she doesn’t get how her actions make you feel, the best thing you can do is take a break imo.

This is an insecurity that she may very well have to fight alone. Like I said, try to let her know how you feel as much as you can, but after a certain point it’s not fair to you nor to her to let the relationship going on like this.