I’m sorry for your anxiety and pain but not for that relationship ending as it was clearly toxic. I’m glad you have learned some lessons from this experience. As hard as it sounds, I would not concern myself with what he is now pursuing or dating… Do not look at old photos or Facebook. Etc. This is self inflicted toture.

Honestly that relationship was miserable on so many levels. You should be happy to be free from such a burden. You are not seeing things clearly now as it is a fresh wound. I suggest taking up mindful meditation 20 min per day. This will help tremendously to cut through the haze. You will be able to better control your thoughts and emotions which are all over the place now. If you are active try hot yoga as well… Please don’t waste precious life and energy on this anymore than is necessary

Don’t beat yourself up for not having appropriate boundaries everyone learns this lesson sooner or later. You are young and already learned this important lesson. Next time you will know better… As far as your anger I suggest doing nothing. Do not vent to him. Simply move on. That is the best revenge and will build momentum for your self esteem. He expects you to he upset, don’t give him the pleasure

Namaste