What should i do with my girlfriend's ex?

Hi, this is basically a sequel to my last thread

So to tldr from that, She had a *** ex that have done bad things with her and she for some reason wanted to reconcile with him back. Out of trust and respect of her feelings, i allowed it with some boundaries. Although i have talked about the discomfort to her. We're also in a long distance relationship which really made everything difficult—

Now it's still going on, she has been breaking alot of the boundaries more often, Talking about him more often. Which made me really uncomfortable and made me feel compared and jealous. And i've made it clear for her everytime. But last argument, she called my feelings as ″***″ and even called me sensitive because i kept whining about him. And of course, i feel really heartbroken from it. It feels like my feelings are being unheard.

Now she's practically became closer to him despite her telling me she won't. Her vent channel seems to be hinting to it too.

″Comfort is comfort, no matter who you got it from am i rite?″

″***, it feels so wrong. but i can't help feeling touched by it″

″No wonder he likes cars″

*Screenshot of his chat*

What should i do with her? I've taken a break from her for one day.