I (19F) just found out my ex-boyfriend (19M) went on a date with my coworker (25F) and are possibly dating, and I wany to confront him but I don't want my current boyfriend (19M) to think I am not over my ex.

For some context, my ex and I had been dating for 5 years before I broke up with him last September. We proceeded to have an on and off connection, either hooking up or trying to be friends again, but it never lasted long and we never stopped talking for very long either. Not long after we broke up (probably a month and a bit) I ended up bringing him to hang out with me and my work friends, where we went drinking together. That night he had flirted with two of my work friends, I just let him because I didn't think I had the right to tell him to stop because we weren't dating anymore.

The day after and a few times after that I had actually asked if he could please not date or sleep with any of my friends or coworkers, as I did not want to have to hear about his love life through one of my own friends - or see him be lovey-dovey at my own work. I had even specifically name dropped this one girl we will call J (25F), because I knew she was his type and she is much more beautiful than I am.

I was pretty good friends with J, she even stayed over at my house once. But recently, I have been feeling a little iffy towards her - it felt very petty but I have been a bit jealous that she is doing a tattoo apprenticeship (my dream job that I plan to start later this year) - and also I can never get out of my head that my ex liked her. I have been feeling like she is pulling away from me and she never tries to contact me anymore or talk to me at work, which we used to do a lot.

Then, this morning I checked my phone and saw that she had uploaded a photobooth pic to her story, and lo and behold - my ex is in that photo? I tap to the next photo and there is a photo of her in his car while he's driving, and then another with the both of them and two other people (I am assuming they are her friends). I was distraught, I don't think I have ever been angrier than when I saw those photos.

Now I want to go yell and confront him, but I feel like it would be wrong of me to when I have a new, loving boyfriend. It just hurts so much that he went for the one person I would be most upset about - that he knew I would be upset about. He could have gone for anyone else but he went for her.

I just need some advice please, and please let me know if it would be wrong of me to go confront my ex.

Edit: I have talked about this to my boyfriend - he trusts me and my feelings about this matter and understands it is upsetting, if not to confront my ex do you think I should mention this to my friend?

Edit: removed comment about age difference, was unnecessary, I think I was just being bitter.

Edit: I feel I should mention some context that my ex got very mad at me just for sleeping with another guy (this was before meeting my current boyfriend) and flipped out on me, telling me that I was disgusting and he couldn't see me the same now that he was no longer the only person to sleep with me (he had already slept with multiple women at this point and was slut shaming me for sleeping with 1 man)